+typedef void (*XferMsgsAsyncUserCallback) (ModestMailOperation *mail_op,
+ gpointer user_data);
+
+
+/**
+ * XferFolderAsyncUserCallback:
+ *
+ * @obj: a #GObject generic object which has created current mail operation.
+ * @new_folder: the new instance of the #TnyFolder that has been transferred
+ * @user_data: generic data passed to user defined function.
+ *
+ * This function will be called after transfer_msgs_cb private function, which is
+ * used as tinymail operation callback. The private function fills private
+ * fields of mail operation and calls user defined callback if it exists.
+ */
+typedef void (*XferFolderAsyncUserCallback) (ModestMailOperation *mail_op,
+ TnyFolder *new_folder,
+ gpointer user_data);