code: private CompletableFuture<Integer> send(boolean mapconvable, Object message, boolean last) {
          if (message instanceof CompletableFuture) {
              return ((CompletableFuture) message).thenCompose((json) -> {
                  if (json == null || json instanceof CharSequence || json instanceof byte[]) {
                      return sendPacket(new WebSocketPacket((Serializable) json, last));
                  } else if (message instanceof WebSocketPacket) {
                      return sendPacket((WebSocketPacket) message);
                  } else {
                      return sendPacket(new WebSocketPacket(getSendConvert(), mapconvable, json, last));
                  }
              }
docs: 给自身发送消息, 消息类型是Object[]
  
  @param mapconvable 是否convertMapTo
  @param message     不可为空, 只能是String或byte[]或可JavaBean对象，或Object[]
  @param last        是否最后一条
  
  @return 0表示成功， 非0表示错误码