SilcBool silc_schedule_one(SilcSchedule schedule, int timeout_usecs);

    Same as the silc_schedule but runs the scheduler only one round
    and then returns.  This function is handy when the SILC scheduler
    is used inside some other external scheduler, for example.  If
    the `timeout_usecs' is non-negative a timeout will be added to the
    scheduler.  The function will not return in this timeout unless
    some other event occurs.

    Typically this would be called from a timeout or idle task
    periodically (typically from 5-50 ms) to schedule SILC tasks.  In
    this case the `timeout_usecs' is usually 0 to make the function
    return immediately.