add keepalive

src/interface.jl

@@ -131,7 +131,7 @@ Base.@kwdef mutable struct mqttClient
     subStatus::Bool= false
     boottime::DateTime= Dates.now()
     retainedMsgCleared= false
-
+    keepalive::Int= 60
 end
 function mqttClient(kwargs::NamedTuple)
 
@@ -149,7 +149,7 @@ function mqttClient(kwargs::NamedTuple)
         s.clientInstance = Mosquitto.Client()
     end
 
-    # connect
+    # connect to broker for the 1st time
     mqttConnect!(s)
 
     return s
@@ -162,7 +162,7 @@ function mqttConnect!(client::mqttClient)
                                     password=client.password)
         client.connectStatus = result == 0 ? true : false
     else
-        result = Mosquitto.connect(client.clientInstance, client.broker, client.port)
+        result = Mosquitto.connect(client.clientInstance, client.broker, client.port, keepalive=client.keepalive)
         client.connectStatus = result == 0 ? true : false
     end
 end
@@ -209,7 +209,7 @@ function mqttReconnect!(client::mqttClient)
         Mosquitto.disconnect(client.clientInstance) # disconnect to release port before attemping new connection
 
         if client.userName === nothing    # check if the member needs username/password
-            result = Mosquitto.connect(client.clientInstance, client.broker, client.port)
+            result = Mosquitto.connect(client.clientInstance, client.broker, client.port, keepalive=client.keepalive)
             client.connectStatus = result == 0 ? true : false
         else
             result = Mosquitto.connect(client.clientInstance, client.broker, client.port,