xbt_assert(MSG_task_get_sender(task), "No sender received");
XBT_INFO("Got a message sent by '%s'",
MSG_process_get_name(MSG_task_get_sender(task)));
xbt_assert(MSG_task_get_sender(task), "No sender received");
XBT_INFO("Got a message sent by '%s'",
MSG_process_get_name(MSG_task_get_sender(task)));