code: private void onBytesRead(int bytesRead) {
          unnotifiedByteCount += bytesRead;
          if (unnotifiedByteCount >= notifyThresHold) {
              onNotifyBytesRead();
              notifiedByteCount += unnotifiedByteCount;
              unnotifiedByteCount = 0;
          }
      }
docs: Upon reading the given number of bytes.
  The default behavior is to accumulate the byte count and only fire off
  a notification by invoking {@link #onNotifyBytesRead()} if the count
  has exceeded the threshold.