[Network] Do not dispose objects after the callback is over, that is too aggressive, perhaps do this for all other transient objects as well

src/Network/NWConnection.cs

@@ -187,7 +187,6 @@ namespace Network {
 			if (del != null){
 				var x = new NWPath (path, owns: false);
 			        del (x);
-				x.Dispose ();
 			}
 		}
 		

src/Network/NWListener.cs

@@ -199,7 +199,6 @@ namespace Network {
 			if (del != null){
 				var nwconnection = new NWConnection (connection, owns: false);
 			        del (nwconnection);
-				nwconnection.Dispose ();
 			}
 		}