SilcBool silc_schedule_task_del(SilcSchedule schedule, SilcTask task);

    Deletes the `task' from the scheduler indicated by the `schedule'.
    After deleting the task it is guaranteed that the task callback
    will not be called. If the `task' is SILC_ALL_TASKS then all
    tasks is removed from the scheduler.  Returns always TRUE.

    It is safe to call this function in any place. Tasks may be removed
    in task callbacks (including in the task's own task callback) and
    in multi-threaded environment in other threads as well.