Added feature to embed data on asynchronous calls.

sjrpc/core/rpcconnection.py

@@ -266,11 +266,18 @@ class RpcConnection(object):
         :param \*\*kwargs: the keyword arguments for the call
         :return: the message id of the call
         '''
-        
+
+        # Extract _data from argument:
+        if '_data' in kwargs:
+            data = kwargs['_data']
+            del kwargs['_data']
+        else:
+            data = None
+
         # Send the call to the peer:
         msg_id = self._send_call(method_name, *args, **kwargs)
 
-        self._calls[msg_id] = {'async': True}
+        self._calls[msg_id] = {'async': True, 'data': data}
 
         return msg_id
 
@@ -323,6 +330,7 @@ class RpcConnection(object):
                 else:
                     # Else, it's an asynchonous call, so, we need to notify
                     # manager that the response has been received:
+                    message['data'] = call['data']
                     self._manager.signal_arrival(message)
 
                     # Message will be deleted from the call list by the