refactor: update data type for network payload

Author: sagar-deriv

lib/services/connection/call_manager/call_history.dart

@@ -44,7 +44,7 @@ class CallHistory implements CallHistoryProvider {
         NetworkPayload(
             method: method,
             body: message,
-            direction: 'RECEIVED',
+            direction: NetworkDirections.received,
             timeStamp: timestamp),
       );
     }
@@ -65,7 +65,7 @@ class CallHistory implements CallHistoryProvider {
         NetworkPayload(
             method: method,
             body: message,
-            direction: 'SENT',
+            direction: NetworkDirections.sent,
             timeStamp: timestamp),
       );
     }

lib/services/interfaces/call_history_provider.dart

@@ -22,8 +22,16 @@ class NetworkPayload {
   final Object body;
 
   /// direction of the api i.e SENT or RECEIVED.
-  final String direction;
+  final NetworkDirections direction;
 
   /// time of the api.
   final int timeStamp;
 }
+
+enum NetworkDirections {
+  /// Going out from the web socket.
+  sent,
+
+  /// Coming in from the web socket.
+  received
+}