persist network plugin state

Summary:
This saved the state of the network plugin even when switching between plugins using persistedState.
A bug in the Android implementation didn't clear the events that were already sent to the desktop.

Reviewed By: jknoxville

Differential Revision: D8752098

fbshipit-source-id: 152ec5da83958ad8124686f780d39983cbce563f

android/plugins/common/RingBuffer.java

@@ -25,6 +25,10 @@ final class RingBuffer<T> {
     mBuffer.add(item);
   }
 
+  void clear() {
+    mBuffer.clear();
+  }
+
   List<T> asList() {
     return mBuffer;
   }