Merge changes I756cb844,I79b63c68 into main

* changes:
  Rename TimerFileDescriptor to RealtimeScheduler
  Enhance TimerFileDescriptor to schedule multiple tasks
diff --git a/staticlibs/device/com/android/net/module/util/RealtimeScheduler.java b/staticlibs/device/com/android/net/module/util/RealtimeScheduler.java
new file mode 100644
index 0000000..bc3b3a5
--- /dev/null
+++ b/staticlibs/device/com/android/net/module/util/RealtimeScheduler.java
@@ -0,0 +1,324 @@
+/*
+ * Copyright (C) 2024 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.net.module.util;
+
+import static android.os.MessageQueue.OnFileDescriptorEventListener.EVENT_ERROR;
+import static android.os.MessageQueue.OnFileDescriptorEventListener.EVENT_INPUT;
+
+import android.os.Handler;
+import android.os.Looper;
+import android.os.Message;
+import android.os.MessageQueue;
+import android.os.ParcelFileDescriptor;
+import android.os.SystemClock;
+import android.util.CloseGuard;
+import android.util.Log;
+
+import androidx.annotation.NonNull;
+
+import java.io.IOException;
+import java.util.PriorityQueue;
+
+/**
+ * Represents a realtime scheduler object used for scheduling tasks with precise delays.
+ * Compared to {@link Handler#postDelayed}, this class offers enhanced accuracy for delayed
+ * callbacks by accounting for periods when the device is in deep sleep.
+ *
+ *  <p> This class is designed for use exclusively from the handler thread.
+ *
+ * **Usage Examples:**
+ *
+ * ** Scheduling recurring tasks with the same RealtimeScheduler **
+ *
+ * ```java
+ * // Create a RealtimeScheduler
+ * final RealtimeScheduler scheduler = new RealtimeScheduler(handler);
+ *
+ * // Schedule a new task with a delay.
+ * scheduler.postDelayed(() -> taskToExecute(), delayTime);
+ *
+ * // Once the delay has elapsed, and the task is running, schedule another task.
+ * scheduler.postDelayed(() -> anotherTaskToExecute(), anotherDelayTime);
+ *
+ * // Remember to close the RealtimeScheduler after all tasks have finished running.
+ * scheduler.close();
+ * ```
+ */
+public class RealtimeScheduler {
+    private static final String TAG = RealtimeScheduler.class.getSimpleName();
+    // EVENT_ERROR may be generated even if not specified, as per its javadoc.
+    private static final int FD_EVENTS = EVENT_INPUT | EVENT_ERROR;
+    private final CloseGuard mGuard = new CloseGuard();
+    @NonNull
+    private final Handler mHandler;
+    @NonNull
+    private final MessageQueue mQueue;
+    @NonNull
+    private final ParcelFileDescriptor mParcelFileDescriptor;
+    private final int mFdInt;
+
+    private final PriorityQueue<Task> mTaskQueue;
+
+    /**
+     * An abstract class for defining tasks that can be executed using a {@link Handler}.
+     */
+    private abstract static class Task implements Comparable<Task> {
+        private final long mRunTimeMs;
+        private final long mCreatedTimeNs = SystemClock.elapsedRealtimeNanos();
+
+        /**
+         * create a task with a run time
+         */
+        Task(long runTimeMs) {
+            mRunTimeMs = runTimeMs;
+        }
+
+        /**
+         * Executes the task using the provided {@link Handler}.
+         *
+         * @param handler The {@link Handler} to use for executing the task.
+         */
+        abstract void post(Handler handler);
+
+        @Override
+        public int compareTo(@NonNull Task o) {
+            if (mRunTimeMs != o.mRunTimeMs) {
+                return Long.compare(mRunTimeMs, o.mRunTimeMs);
+            }
+            return Long.compare(mCreatedTimeNs, o.mCreatedTimeNs);
+        }
+
+        /**
+         * Returns the run time of the task.
+         */
+        public long getRunTimeMs() {
+            return mRunTimeMs;
+        }
+    }
+
+    /**
+     * A task that sends a {@link Message} using a {@link Handler}.
+     */
+    private static class MessageTask extends Task {
+        private final Message mMessage;
+
+        MessageTask(Message message, long runTimeMs) {
+            super(runTimeMs);
+            mMessage = message;
+        }
+
+        /**
+         * Sends the {@link Message} using the provided {@link Handler}.
+         *
+         * @param handler The {@link Handler} to use for sending the message.
+         */
+        @Override
+        public void post(Handler handler) {
+            handler.sendMessage(mMessage);
+        }
+    }
+
+    /**
+     * A task that posts a {@link Runnable} to a {@link Handler}.
+     */
+    private static class RunnableTask extends Task {
+        private final Runnable mRunnable;
+
+        RunnableTask(Runnable runnable, long runTimeMs) {
+            super(runTimeMs);
+            mRunnable = runnable;
+        }
+
+        /**
+         * Posts the {@link Runnable} to the provided {@link Handler}.
+         *
+         * @param handler The {@link Handler} to use for posting the runnable.
+         */
+        @Override
+        public void post(Handler handler) {
+            handler.post(mRunnable);
+        }
+    }
+
+    /**
+     * The RealtimeScheduler constructor
+     *
+     * Note: The constructor is currently safe to call on another thread because it only sets final
+     * members and registers the event to be called on the handler.
+     */
+    public RealtimeScheduler(@NonNull Handler handler) {
+        mFdInt = TimerFdUtils.createTimerFileDescriptor();
+        mParcelFileDescriptor = ParcelFileDescriptor.adoptFd(mFdInt);
+        mHandler = handler;
+        mQueue = handler.getLooper().getQueue();
+        mTaskQueue = new PriorityQueue<>();
+        registerFdEventListener();
+
+        mGuard.open("close");
+    }
+
+    private boolean enqueueTask(@NonNull Task task, long delayMs) {
+        ensureRunningOnCorrectThread();
+        if (delayMs <= 0L) {
+            task.post(mHandler);
+            return true;
+        }
+        if (mTaskQueue.isEmpty() || task.compareTo(mTaskQueue.peek()) < 0) {
+            if (!TimerFdUtils.setExpirationTime(mFdInt, delayMs)) {
+                return false;
+            }
+        }
+        mTaskQueue.add(task);
+        return true;
+    }
+
+    /**
+     * Set a runnable to be executed after a specified delay.
+     *
+     * If delayMs is less than or equal to 0, the runnable will be executed immediately.
+     *
+     * @param runnable the runnable to be executed
+     * @param delayMs the delay time in milliseconds
+     * @return true if the task is scheduled successfully, false otherwise.
+     */
+    public boolean postDelayed(@NonNull Runnable runnable, long delayMs) {
+        return enqueueTask(new RunnableTask(runnable, SystemClock.elapsedRealtime() + delayMs),
+                delayMs);
+    }
+
+    /**
+     * Remove a scheduled runnable.
+     *
+     * @param runnable the runnable to be removed
+     */
+    public void removeDelayedRunnable(@NonNull Runnable runnable) {
+        ensureRunningOnCorrectThread();
+        mTaskQueue.removeIf(task -> task instanceof RunnableTask
+                && ((RunnableTask) task).mRunnable == runnable);
+    }
+
+    /**
+     * Set a message to be sent after a specified delay.
+     *
+     * If delayMs is less than or equal to 0, the message will be sent immediately.
+     *
+     * @param msg the message to be sent
+     * @param delayMs the delay time in milliseconds
+     * @return true if the message is scheduled successfully, false otherwise.
+     */
+    public boolean sendDelayedMessage(Message msg, long delayMs) {
+
+        return enqueueTask(new MessageTask(msg, SystemClock.elapsedRealtime() + delayMs), delayMs);
+    }
+
+    /**
+     * Remove a scheduled message.
+     *
+     * @param what the message to be removed
+     */
+    public void removeDelayedMessage(int what) {
+        ensureRunningOnCorrectThread();
+        mTaskQueue.removeIf(task -> task instanceof MessageTask
+                && ((MessageTask) task).mMessage.what == what);
+    }
+
+    /**
+     * Close the RealtimeScheduler. This implementation closes the underlying
+     * OS resources allocated to represent this stream.
+     */
+    public void close() {
+        ensureRunningOnCorrectThread();
+        unregisterAndDestroyFd();
+    }
+
+    private void registerFdEventListener() {
+        mQueue.addOnFileDescriptorEventListener(
+                mParcelFileDescriptor.getFileDescriptor(),
+                FD_EVENTS,
+                (fd, events) -> {
+                    if (!isRunning()) {
+                        return 0;
+                    }
+                    if ((events & EVENT_INPUT) != 0) {
+                        handleExpiration();
+                    }
+                    return FD_EVENTS;
+                });
+    }
+
+    private boolean isRunning() {
+        return mParcelFileDescriptor.getFileDescriptor().valid();
+    }
+
+    private void handleExpiration() {
+        long currentTimeMs = SystemClock.elapsedRealtime();
+        while (!mTaskQueue.isEmpty()) {
+            final Task task = mTaskQueue.peek();
+            currentTimeMs = SystemClock.elapsedRealtime();
+            if (currentTimeMs < task.getRunTimeMs()) {
+                break;
+            }
+            task.post(mHandler);
+            mTaskQueue.poll();
+        }
+
+
+        if (!mTaskQueue.isEmpty()) {
+            // Using currentTimeMs ensures that the calculated expiration time
+            // is always positive.
+            if (!TimerFdUtils.setExpirationTime(mFdInt,
+                    mTaskQueue.peek().getRunTimeMs() - currentTimeMs)) {
+                // If setting the expiration time fails, clear the task queue.
+                Log.wtf(TAG, "Failed to set expiration time");
+                mTaskQueue.clear();
+            }
+        } else {
+            // We have to clean up the timer if no tasks are left. Otherwise, the timer will keep
+            // being triggered.
+            TimerFdUtils.setExpirationTime(mFdInt, 0);
+        }
+    }
+
+    private void unregisterAndDestroyFd() {
+        if (mGuard != null) {
+            mGuard.close();
+        }
+
+        mQueue.removeOnFileDescriptorEventListener(mParcelFileDescriptor.getFileDescriptor());
+        try {
+            mParcelFileDescriptor.close();
+        } catch (IOException exception) {
+            Log.e(TAG, "close ParcelFileDescriptor failed. ", exception);
+        }
+    }
+
+    private void ensureRunningOnCorrectThread() {
+        if (mHandler.getLooper() != Looper.myLooper()) {
+            throw new IllegalStateException(
+                    "Not running on Handler thread: " + Thread.currentThread().getName());
+        }
+    }
+
+    @SuppressWarnings("Finalize")
+    @Override
+    protected void finalize() throws Throwable {
+        if (mGuard != null) {
+            mGuard.warnIfOpen();
+        }
+        super.finalize();
+    }
+}
diff --git a/staticlibs/device/com/android/net/module/util/TimerFileDescriptor.java b/staticlibs/device/com/android/net/module/util/TimerFileDescriptor.java
deleted file mode 100644
index dbbccc5..0000000
--- a/staticlibs/device/com/android/net/module/util/TimerFileDescriptor.java
+++ /dev/null
@@ -1,254 +0,0 @@
-/*
- * Copyright (C) 2024 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package com.android.net.module.util;
-
-import static android.os.MessageQueue.OnFileDescriptorEventListener.EVENT_ERROR;
-import static android.os.MessageQueue.OnFileDescriptorEventListener.EVENT_INPUT;
-
-import android.os.Handler;
-import android.os.Looper;
-import android.os.Message;
-import android.os.MessageQueue;
-import android.os.ParcelFileDescriptor;
-import android.util.CloseGuard;
-import android.util.Log;
-
-import androidx.annotation.NonNull;
-import androidx.annotation.Nullable;
-
-import java.io.IOException;
-
-/**
- * Represents a Timer file descriptor object used for scheduling tasks with precise delays.
- * Compared to {@link Handler#postDelayed}, this class offers enhanced accuracy for delayed
- * callbacks by accounting for periods when the device is in deep sleep.
- *
- *  <p> This class is designed for use exclusively from the handler thread.
- *
- * **Usage Examples:**
- *
- * ** Scheduling recurring tasks with the same TimerFileDescriptor **
- *
- * ```java
- * // Create a TimerFileDescriptor
- * final TimerFileDescriptor timerFd = new TimerFileDescriptor(handler);
- *
- * // Schedule a new task with a delay.
- * timerFd.setDelayedTask(() -> taskToExecute(), delayTime);
- *
- * // Once the delay has elapsed, and the task is running, schedule another task.
- * timerFd.setDelayedTask(() -> anotherTaskToExecute(), anotherDelayTime);
- *
- * // Remember to close the TimerFileDescriptor after all tasks have finished running.
- * timerFd.close();
- * ```
- */
-public class TimerFileDescriptor {
-    private static final String TAG = TimerFileDescriptor.class.getSimpleName();
-    // EVENT_ERROR may be generated even if not specified, as per its javadoc.
-    private static final int FD_EVENTS = EVENT_INPUT | EVENT_ERROR;
-    private final CloseGuard mGuard = new CloseGuard();
-    @NonNull
-    private final Handler mHandler;
-    @NonNull
-    private final MessageQueue mQueue;
-    @NonNull
-    private final ParcelFileDescriptor mParcelFileDescriptor;
-    private final int mFdInt;
-    @Nullable
-    private ITask mTask;
-
-    /**
-     * An interface for defining tasks that can be executed using a {@link Handler}.
-     */
-    public interface ITask {
-        /**
-         * Executes the task using the provided {@link Handler}.
-         *
-         * @param handler The {@link Handler} to use for executing the task.
-         */
-        void post(Handler handler);
-    }
-
-    /**
-     * A task that sends a {@link Message} using a {@link Handler}.
-     */
-    public static class MessageTask implements ITask {
-        private final Message mMessage;
-
-        public MessageTask(Message message) {
-            mMessage = message;
-        }
-
-        /**
-         * Sends the {@link Message} using the provided {@link Handler}.
-         *
-         * @param handler The {@link Handler} to use for sending the message.
-         */
-        @Override
-        public void post(Handler handler) {
-            handler.sendMessage(mMessage);
-        }
-    }
-
-    /**
-     * A task that posts a {@link Runnable} to a {@link Handler}.
-     */
-    public static class RunnableTask implements ITask {
-        private final Runnable mRunnable;
-
-        public RunnableTask(Runnable runnable) {
-            mRunnable = runnable;
-        }
-
-        /**
-         * Posts the {@link Runnable} to the provided {@link Handler}.
-         *
-         * @param handler The {@link Handler} to use for posting the runnable.
-         */
-        @Override
-        public void post(Handler handler) {
-            handler.post(mRunnable);
-        }
-    }
-
-    /**
-     * TimerFileDescriptor constructor
-     *
-     * Note: The constructor is currently safe to call on another thread because it only sets final
-     * members and registers the event to be called on the handler.
-     */
-    public TimerFileDescriptor(@NonNull Handler handler) {
-        mFdInt = TimerFdUtils.createTimerFileDescriptor();
-        mParcelFileDescriptor = ParcelFileDescriptor.adoptFd(mFdInt);
-        mHandler = handler;
-        mQueue = handler.getLooper().getQueue();
-        registerFdEventListener();
-
-        mGuard.open("close");
-    }
-
-    /**
-     * Set a task to be executed after a specified delay.
-     *
-     * <p> A task can only be scheduled once at a time. Cancel previous scheduled task before the
-     *     new task is scheduled.
-     *
-     * @param task the task to be executed
-     * @param delayMs the delay time in milliseconds
-     * @throws IllegalArgumentException if try to replace the current scheduled task
-     * @throws IllegalArgumentException if the delay time is less than 0
-     */
-    public void setDelayedTask(@NonNull ITask task, long delayMs) {
-        ensureRunningOnCorrectThread();
-        if (mTask != null) {
-            throw new IllegalArgumentException("task is already scheduled");
-        }
-        if (delayMs <= 0L) {
-            task.post(mHandler);
-            return;
-        }
-
-        if (TimerFdUtils.setExpirationTime(mFdInt, delayMs)) {
-            mTask = task;
-        }
-    }
-
-    /**
-     * Cancel the scheduled task.
-     */
-    public void cancelTask() {
-        ensureRunningOnCorrectThread();
-        if (mTask == null) return;
-
-        TimerFdUtils.setExpirationTime(mFdInt, 0 /* delayMs */);
-        mTask = null;
-    }
-
-    /**
-     * Check if there is a scheduled task.
-     */
-    public boolean hasDelayedTask() {
-        ensureRunningOnCorrectThread();
-        return mTask != null;
-    }
-
-    /**
-     * Close the TimerFileDescriptor. This implementation closes the underlying
-     * OS resources allocated to represent this stream.
-     */
-    public void close() {
-        ensureRunningOnCorrectThread();
-        unregisterAndDestroyFd();
-    }
-
-    private void registerFdEventListener() {
-        mQueue.addOnFileDescriptorEventListener(
-                mParcelFileDescriptor.getFileDescriptor(),
-                FD_EVENTS,
-                (fd, events) -> {
-                    if (!isRunning()) {
-                        return 0;
-                    }
-                    if ((events & EVENT_INPUT) != 0) {
-                        handleExpiration();
-                    }
-                    return FD_EVENTS;
-                });
-    }
-
-    private boolean isRunning() {
-        return mParcelFileDescriptor.getFileDescriptor().valid();
-    }
-
-    private void handleExpiration() {
-        // Execute the task
-        if (mTask != null) {
-            mTask.post(mHandler);
-            mTask = null;
-        }
-    }
-
-    private void unregisterAndDestroyFd() {
-        if (mGuard != null) {
-            mGuard.close();
-        }
-
-        mQueue.removeOnFileDescriptorEventListener(mParcelFileDescriptor.getFileDescriptor());
-        try {
-            mParcelFileDescriptor.close();
-        } catch (IOException exception) {
-            Log.e(TAG, "close ParcelFileDescriptor failed. ", exception);
-        }
-    }
-
-    private void ensureRunningOnCorrectThread() {
-        if (mHandler.getLooper() != Looper.myLooper()) {
-            throw new IllegalStateException(
-                    "Not running on Handler thread: " + Thread.currentThread().getName());
-        }
-    }
-
-    @SuppressWarnings("Finalize")
-    @Override
-    protected void finalize() throws Throwable {
-        if (mGuard != null) {
-            mGuard.warnIfOpen();
-        }
-        super.finalize();
-    }
-}
diff --git a/staticlibs/tests/unit/Android.bp b/staticlibs/tests/unit/Android.bp
index 9d1d291..f4f1ea9 100644
--- a/staticlibs/tests/unit/Android.bp
+++ b/staticlibs/tests/unit/Android.bp
@@ -28,6 +28,7 @@
         "net-utils-device-common-struct-base",
         "net-utils-device-common-wear",
         "net-utils-service-connectivity",
+        "truth",
     ],
     libs: [
         "android.test.runner.stubs",
diff --git a/staticlibs/tests/unit/src/com/android/net/module/util/RealtimeSchedulerTest.kt b/staticlibs/tests/unit/src/com/android/net/module/util/RealtimeSchedulerTest.kt
new file mode 100644
index 0000000..30b530f
--- /dev/null
+++ b/staticlibs/tests/unit/src/com/android/net/module/util/RealtimeSchedulerTest.kt
@@ -0,0 +1,140 @@
+/*
+ * Copyright (C) 2024 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.net.module.util
+
+import android.os.Build
+import android.os.ConditionVariable
+import android.os.Handler
+import android.os.HandlerThread
+import android.os.Looper
+import android.os.Message
+import android.os.SystemClock
+import androidx.test.filters.SmallTest
+import com.android.testutils.DevSdkIgnoreRule
+import com.android.testutils.DevSdkIgnoreRunner
+import com.android.testutils.tryTest
+import com.android.testutils.visibleOnHandlerThread
+import com.google.common.collect.Range
+import com.google.common.truth.Truth.assertThat
+import kotlin.test.assertEquals
+import org.junit.After
+import org.junit.Test
+import org.junit.runner.RunWith
+
+@DevSdkIgnoreRunner.MonitorThreadLeak
+@RunWith(DevSdkIgnoreRunner::class)
+@SmallTest
+@DevSdkIgnoreRule.IgnoreUpTo(Build.VERSION_CODES.R)
+class RealtimeSchedulerTest {
+
+    private val TIMEOUT_MS = 1000L
+    private val TOLERANCE_MS = 50L
+    private class TestHandler(looper: Looper) : Handler(looper) {
+        override fun handleMessage(msg: Message) {
+            val pair = msg.obj as Pair<ConditionVariable, MutableList<Long>>
+            val cv = pair.first
+            cv.open()
+            val executionTimes = pair.second
+            executionTimes.add(SystemClock.elapsedRealtime())
+        }
+    }
+    private val thread = HandlerThread(RealtimeSchedulerTest::class.simpleName).apply { start() }
+    private val handler by lazy { TestHandler(thread.looper) }
+
+    @After
+    fun tearDown() {
+        thread.quitSafely()
+        thread.join()
+    }
+
+    @Test
+    fun testMultiplePostDelayedTasks() {
+        val scheduler = RealtimeScheduler(handler)
+        tryTest {
+            val initialTimeMs = SystemClock.elapsedRealtime()
+            val executionTimes = mutableListOf<Long>()
+            val cv = ConditionVariable()
+            handler.post {
+                scheduler.postDelayed(
+                    { executionTimes.add(SystemClock.elapsedRealtime() - initialTimeMs) }, 0)
+                scheduler.postDelayed(
+                    { executionTimes.add(SystemClock.elapsedRealtime() - initialTimeMs) }, 200)
+                val toBeRemoved = Runnable {
+                    executionTimes.add(SystemClock.elapsedRealtime() - initialTimeMs)
+                }
+                scheduler.postDelayed(toBeRemoved, 250)
+                scheduler.removeDelayedRunnable(toBeRemoved)
+                scheduler.postDelayed(
+                    { executionTimes.add(SystemClock.elapsedRealtime() - initialTimeMs) }, 100)
+                scheduler.postDelayed({
+                    executionTimes.add(SystemClock.elapsedRealtime() - initialTimeMs)
+                    cv.open() }, 300)
+            }
+            cv.block(TIMEOUT_MS)
+            assertEquals(4, executionTimes.size)
+            assertThat(executionTimes[0]).isIn(Range.closed(0L, TOLERANCE_MS))
+            assertThat(executionTimes[1]).isIn(Range.closed(100L, 100 + TOLERANCE_MS))
+            assertThat(executionTimes[2]).isIn(Range.closed(200L, 200 + TOLERANCE_MS))
+            assertThat(executionTimes[3]).isIn(Range.closed(300L, 300 + TOLERANCE_MS))
+        } cleanup {
+            visibleOnHandlerThread(handler) { scheduler.close() }
+        }
+    }
+
+    @Test
+    fun testMultipleSendDelayedMessages() {
+        val scheduler = RealtimeScheduler(handler)
+        tryTest {
+            val MSG_ID_0 = 0
+            val MSG_ID_1 = 1
+            val MSG_ID_2 = 2
+            val MSG_ID_3 = 3
+            val MSG_ID_4 = 4
+            val initialTimeMs = SystemClock.elapsedRealtime()
+            val executionTimes = mutableListOf<Long>()
+            val cv = ConditionVariable()
+            handler.post {
+                scheduler.sendDelayedMessage(
+                    Message.obtain(handler, MSG_ID_0, Pair(ConditionVariable(), executionTimes)), 0)
+                scheduler.sendDelayedMessage(
+                    Message.obtain(handler, MSG_ID_1, Pair(ConditionVariable(), executionTimes)),
+                    200)
+                scheduler.sendDelayedMessage(
+                    Message.obtain(handler, MSG_ID_4, Pair(ConditionVariable(), executionTimes)),
+                    250)
+                scheduler.removeDelayedMessage(MSG_ID_4)
+                scheduler.sendDelayedMessage(
+                    Message.obtain(handler, MSG_ID_2, Pair(ConditionVariable(), executionTimes)),
+                    100)
+                scheduler.sendDelayedMessage(
+                    Message.obtain(handler, MSG_ID_3, Pair(cv, executionTimes)),
+                    300)
+            }
+            cv.block(TIMEOUT_MS)
+            assertEquals(4, executionTimes.size)
+            assertThat(executionTimes[0] - initialTimeMs).isIn(Range.closed(0L, TOLERANCE_MS))
+            assertThat(executionTimes[1] - initialTimeMs)
+                .isIn(Range.closed(100L, 100 + TOLERANCE_MS))
+            assertThat(executionTimes[2] - initialTimeMs)
+                .isIn(Range.closed(200L, 200 + TOLERANCE_MS))
+            assertThat(executionTimes[3] - initialTimeMs)
+                .isIn(Range.closed(300L, 300 + TOLERANCE_MS))
+        } cleanup {
+            visibleOnHandlerThread(handler) { scheduler.close() }
+        }
+    }
+}
diff --git a/staticlibs/tests/unit/src/com/android/net/module/util/TimerFileDescriptorTest.kt b/staticlibs/tests/unit/src/com/android/net/module/util/TimerFileDescriptorTest.kt
deleted file mode 100644
index f5e47c9..0000000
--- a/staticlibs/tests/unit/src/com/android/net/module/util/TimerFileDescriptorTest.kt
+++ /dev/null
@@ -1,114 +0,0 @@
-/*
- * Copyright (C) 2024 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package com.android.net.module.util
-
-import android.os.Build
-import android.os.ConditionVariable
-import android.os.Handler
-import android.os.HandlerThread
-import android.os.Looper
-import android.os.Message
-import androidx.test.filters.SmallTest
-import com.android.net.module.util.TimerFileDescriptor.ITask
-import com.android.net.module.util.TimerFileDescriptor.MessageTask
-import com.android.net.module.util.TimerFileDescriptor.RunnableTask
-import com.android.testutils.DevSdkIgnoreRule
-import com.android.testutils.DevSdkIgnoreRunner
-import com.android.testutils.tryTest
-import com.android.testutils.visibleOnHandlerThread
-import org.junit.After
-import org.junit.Test
-import org.junit.runner.RunWith
-import java.time.Duration
-import java.time.Instant
-import kotlin.test.assertFalse
-import kotlin.test.assertTrue
-
-private const val MSG_TEST = 1
-
-@DevSdkIgnoreRunner.MonitorThreadLeak
-@RunWith(DevSdkIgnoreRunner::class)
-@SmallTest
-@DevSdkIgnoreRule.IgnoreUpTo(Build.VERSION_CODES.R)
-class TimerFileDescriptorTest {
-    private class TestHandler(looper: Looper) : Handler(looper) {
-        override fun handleMessage(msg: Message) {
-            val cv = msg.obj as ConditionVariable
-            cv.open()
-        }
-    }
-    private val thread = HandlerThread(TimerFileDescriptorTest::class.simpleName).apply { start() }
-    private val handler by lazy { TestHandler(thread.looper) }
-
-    @After
-    fun tearDown() {
-        thread.quitSafely()
-        thread.join()
-    }
-
-    private fun assertDelayedTaskPost(
-            timerFd: TimerFileDescriptor,
-            task: ITask,
-            cv: ConditionVariable
-    ) {
-        val delayTime = 10L
-        val startTime1 = Instant.now()
-        handler.post { timerFd.setDelayedTask(task, delayTime) }
-        assertTrue(cv.block(100L /* timeoutMs*/))
-        assertTrue(Duration.between(startTime1, Instant.now()).toMillis() >= delayTime)
-    }
-
-    @Test
-    fun testSetDelayedTask() {
-        val timerFd = TimerFileDescriptor(handler)
-        tryTest {
-            // Verify the delayed task is executed with the self-implemented ITask
-            val cv1 = ConditionVariable()
-            assertDelayedTaskPost(timerFd, { cv1.open() }, cv1)
-
-            // Verify the delayed task is executed with the RunnableTask
-            val cv2 = ConditionVariable()
-            assertDelayedTaskPost(timerFd, RunnableTask{ cv2.open() }, cv2)
-
-            // Verify the delayed task is executed with the MessageTask
-            val cv3 = ConditionVariable()
-            assertDelayedTaskPost(timerFd, MessageTask(handler.obtainMessage(MSG_TEST, cv3)), cv3)
-        } cleanup {
-            visibleOnHandlerThread(handler) { timerFd.close() }
-        }
-    }
-
-    @Test
-    fun testCancelTask() {
-        // The task is posted and canceled within the same handler loop, so the short delay used
-        // here won't cause flakes.
-        val delayTime = 10L
-        val timerFd = TimerFileDescriptor(handler)
-        val cv = ConditionVariable()
-        tryTest {
-            handler.post {
-                timerFd.setDelayedTask({ cv.open() }, delayTime)
-                assertTrue(timerFd.hasDelayedTask())
-                timerFd.cancelTask()
-                assertFalse(timerFd.hasDelayedTask())
-            }
-            assertFalse(cv.block(20L /* timeoutMs*/))
-        } cleanup {
-            visibleOnHandlerThread(handler) { timerFd.close() }
-        }
-    }
-}