Remove unnecessary byte array allocation:

The `upstreamEvents` byte array may not be used if debugging is
disabled.  Remove the array allocation and retrieve the array
directly when required.

Test: atest TetheringTests
Change-Id: I7e1ddd3ce2e3079f07deebe3dd49aef832b24558
diff --git a/Tethering/src/com/android/networkstack/tethering/metrics/TetheringMetrics.java b/Tethering/src/com/android/networkstack/tethering/metrics/TetheringMetrics.java
index 32c1410..c77f951 100644
--- a/Tethering/src/com/android/networkstack/tethering/metrics/TetheringMetrics.java
+++ b/Tethering/src/com/android/networkstack/tethering/metrics/TetheringMetrics.java
@@ -431,7 +431,6 @@
      * @param reported a NetworkTetheringReported object containing statistics to write
      */
     private void write(@NonNull final NetworkTetheringReported reported) {
-        final byte[] upstreamEvents = reported.getUpstreamEvents().toByteArray();
         mDependencies.write(reported);
         if (DBG) {
             Log.d(
@@ -445,7 +444,7 @@
                     + ", userType: "
                     + reported.getUserType().getNumber()
                     + ", upstreamTypes: "
-                    + Arrays.toString(upstreamEvents)
+                    + Arrays.toString(reported.getUpstreamEvents().toByteArray())
                     + ", durationMillis: "
                     + reported.getDurationMillis());
         }