✨ mica-mqtt-spring-boot-starter 完善。

mica-mqtt-spring-boot-starter/src/main/java/net/dreamlu/iot/mqtt/spring/client/MqttClientTemplate.java

@@ -202,6 +202,15 @@ public class MqttClientTemplate implements InitializingBean, DisposableBean, Ord
 		return client.getContext();
 	}
 
+	/**
+	 * 判断客户端跟服务端是否断开连接
+	 *
+	 * @return 是否断连
+	 */
+	public boolean isDisconnected() {
+		return client.isDisconnected();
+	}
+
 	/**
 	 * 获取 MqttClient
 	 *