code: public void messageSent(Packet message) {
          if (message.getMessage() instanceof VideoData) {
              Number streamId = message.getHeader().getStreamId();
              AtomicInteger pending = pendingVideos.get(streamId.doubleValue());
              if (log.isTraceEnabled()) {
                  log.trace("Stream id: {} pending: {} total pending videos: {}", streamId, pending, pendingVideos.size());
              }
              if (pending != null) {
                  pending.decrementAndGet();
              }
          }
          writtenMessages.incrementAndGet();
      }
docs: Mark message as sent.
  
  @param message
  Message to mark