建议通过setBufferSize与setKeepAlive进行设置 | Suggest to set MQTT_KEEPALIVE and MQTT_MAX_PACKET_SIZE by set method, other than revision the PubSubClient.h

[NirViaje]

eg:

AliyunMQTTclient.setBufferSize(1024);
AliyunMQTTclient.setKeepAlive(60);