code: @Override
      public synchronized void post(byte[] data, int offset, int len) {
          // Log.w(TAG, "post");
          if (isClosed) {
              return;
          }
          try {
              sendProtoPackage(data, offset, len);
          } catch (IOException e) {
              Log.e(TAG, e);
              close();
          }
      }
docs: Public methods