diff --git a/libs/binder/RpcServer.cpp b/libs/binder/RpcServer.cpp
index e31aea0..df7c844 100644
--- a/libs/binder/RpcServer.cpp
+++ b/libs/binder/RpcServer.cpp
@@ -128,16 +128,6 @@
     return ret;
 }
 
-std::unique_ptr<RpcServer::FdTrigger> RpcServer::FdTrigger::make() {
-    auto ret = std::make_unique<RpcServer::FdTrigger>();
-    if (!android::base::Pipe(&ret->mRead, &ret->mWrite)) return nullptr;
-    return ret;
-}
-
-void RpcServer::FdTrigger::trigger() {
-    mWrite.reset();
-}
-
 void RpcServer::join() {
     LOG_ALWAYS_FATAL_IF(!mAgreedExperimental, "no!");
 
@@ -146,7 +136,7 @@
         LOG_ALWAYS_FATAL_IF(!mServer.ok(), "RpcServer must be setup to join.");
         LOG_ALWAYS_FATAL_IF(mShutdownTrigger != nullptr, "Already joined");
         mJoinThreadRunning = true;
-        mShutdownTrigger = FdTrigger::make();
+        mShutdownTrigger = RpcSession::FdTrigger::make();
         LOG_ALWAYS_FATAL_IF(mShutdownTrigger == nullptr, "Cannot create join signaler");
     }
 
diff --git a/libs/binder/RpcSession.cpp b/libs/binder/RpcSession.cpp
index 05fa49e..4efa6bb 100644
--- a/libs/binder/RpcSession.cpp
+++ b/libs/binder/RpcSession.cpp
@@ -113,6 +113,16 @@
     return state()->sendDecStrong(connection.fd(), address);
 }
 
+std::unique_ptr<RpcSession::FdTrigger> RpcSession::FdTrigger::make() {
+    auto ret = std::make_unique<RpcSession::FdTrigger>();
+    if (!android::base::Pipe(&ret->mRead, &ret->mWrite)) return nullptr;
+    return ret;
+}
+
+void RpcSession::FdTrigger::trigger() {
+    mWrite.reset();
+}
+
 status_t RpcSession::readId() {
     {
         std::lock_guard<std::mutex> _l(mMutex);
diff --git a/libs/binder/include/binder/RpcServer.h b/libs/binder/include/binder/RpcServer.h
index 4973400..d1a8627 100644
--- a/libs/binder/include/binder/RpcServer.h
+++ b/libs/binder/include/binder/RpcServer.h
@@ -153,23 +153,6 @@
     void onSessionTerminating(const sp<RpcSession>& session);
 
 private:
-    /** This is not a pipe. */
-    struct FdTrigger {
-        static std::unique_ptr<FdTrigger> make();
-        /**
-         * poll() on this fd for POLLHUP to get notification when trigger is called
-         */
-        base::borrowed_fd readFd() const { return mRead; }
-        /**
-         * Close the write end of the pipe so that the read end receives POLLHUP.
-         */
-        void trigger();
-
-    private:
-        base::unique_fd mWrite;
-        base::unique_fd mRead;
-    };
-
     friend sp<RpcServer>;
     RpcServer();
 
@@ -188,7 +171,7 @@
     std::map<int32_t, sp<RpcSession>> mSessions;
     int32_t mSessionIdCounter = 0;
     bool mJoinThreadRunning = false;
-    std::unique_ptr<FdTrigger> mShutdownTrigger;
+    std::unique_ptr<RpcSession::FdTrigger> mShutdownTrigger;
     std::condition_variable mShutdownCv;
 };
 
diff --git a/libs/binder/include/binder/RpcSession.h b/libs/binder/include/binder/RpcSession.h
index bcc213c..6a60e7e 100644
--- a/libs/binder/include/binder/RpcSession.h
+++ b/libs/binder/include/binder/RpcSession.h
@@ -112,6 +112,23 @@
     friend RpcServer;
     RpcSession();
 
+    /** This is not a pipe. */
+    struct FdTrigger {
+        static std::unique_ptr<FdTrigger> make();
+        /**
+         * poll() on this fd for POLLHUP to get notification when trigger is called
+         */
+        base::borrowed_fd readFd() const { return mRead; }
+        /**
+         * Close the write end of the pipe so that the read end receives POLLHUP.
+         */
+        void trigger();
+
+    private:
+        base::unique_fd mWrite;
+        base::unique_fd mRead;
+    };
+
     status_t readId();
 
     // transfer ownership of thread