mqtt1.1.1 Timed out as no write activity, error code 32002

收发消息比较频繁，运行了几个月突然mqtt报出如下错误 (run several months,This error occurs as follow)：

Timed out as no write activity, keepAlive=20,000 lastOutboundActivity=1,671,150,138,004 lastInboundActivity=1,671,150,136,450 time=1,671,150,178,005 lastPing=0 [2022-12-16 08:22:58.499] ERROR ....ColonyPushCallback 45 - 连接断开，正在重连{} org.eclipse.paho.client.mqttv3.MqttException: Timed out while waiting to write messages to the server at org.eclipse.paho.client.mqttv3.internal.ExceptionHelper.createMqttException(ExceptionHelper.java:31) at org.eclipse.paho.client.mqttv3.internal.ClientState.checkForActivity(ClientState.java:690) at org.eclipse.paho.client.mqttv3.internal.ClientComms.checkForActivity(ClientComms.java:758) at org.eclipse.paho.client.mqttv3.internal.ClientComms.checkForActivity(ClientComms.java:744) at org.eclipse.paho.client.mqttv3.TimerPingSender$PingTask.run(TimerPingSender.java:78) at java.util.TimerThread.mainLoop(Timer.java:555) at java.util.TimerThread.run(Timer.java:505)” [2022-12-16 08:22:58.499] ERROR ...ColonyPushCallback 175 - mqtt发送消息异常: org.eclipse.paho.client.mqttv3.MqttException: 客户机未连接 at org.eclipse.paho.client.mqttv3.internal.ExceptionHelper.createMqttException(ExceptionHelper.java:31) at org.eclipse.paho.client.mqttv3.internal.ClientComms.sendNoWait(ClientComms.java:177) at org.eclipse.paho.client.mqttv3.MqttTopic.publish(MqttTopic.java:116) ... [2022-12-16 08:22:58.499] ERROR ...ColonyPushCallback 175 - mqtt发送消息异常: org.eclipse.paho.client.mqttv3.MqttException: 客户机未连接 at org.eclipse.paho.client.mqttv3.internal.ExceptionHelper.createMqttException(ExceptionHelper.java:31) at org.eclipse.paho.client.mqttv3.internal.ClientComms.sendNoWait(ClientComms.java:177) at org.eclipse.paho.client.mqttv3.MqttTopic.publish(MqttTopic.java:116) ....

code error: 32002

This error occurs for the code

    org.eclipse.paho.client.mqttv3.internal.ClientState#checkForActivity

 if (pingOutstanding == 0 && (time - lastOutboundActivity >= 2*keepAlive)) {
  // I am probably blocked on a write operations as I should have been able to write at least a ping message                                                                                                    
   log.severe(CLASS_NAME,methodName,"642", new Object[]{new Long(this.keepAlive),new Long(lastOutboundActivity),new Long(lastInboundActivity), new Long(time), new Long(lastPing)});

    // A ping has not been sent but I am not progressing on the current write operation. 
    // At this point, assume that the broker has hung and the TCP layer hasn't noticed.

  throw ExceptionHelper.createMqttException(MqttException.REASON_CODE_WRITE_TIMEOUT);
            }

our version is 1.1.1, the reason is ?

eclipse / paho.mqtt.java

mqtt1.1.1 Timed out as no write activity, error code 32002 #982