code: public void addMessageEvent(MessageEvent messageEvent) {
      // Default implementation by invoking addNetworkEvent() so that any existing derived classes,
      // including implementation and the mocked ones, do not need to override this method explicitly.
      Utils.checkNotNull(messageEvent, "messageEvent");
      addNetworkEvent(BaseMessageEventUtils.asNetworkEvent(messageEvent));
    }
docs: Adds a MessageEvent to the {@code Span}.
  
  <p>This function can be used by higher level applications to record messaging event.
  
  <p>This method should always be overridden by users whose API versions are larger or equal to
  {@code 0.12}.
  
  @param messageEvent the message to add.
  @since 0.12