Fiber::Scheduler#yield

VALUE
rb_fiber_scheduler_yield(VALUE scheduler)
{
    // First try to call the scheduler's yield method, if it exists:
    VALUE result = rb_check_funcall(scheduler, id_yield, 0, NULL);
    if (!UNDEF_P(result)) return result;

    // Otherwise, we can emulate yield by sleeping for 0 seconds:
    return rb_fiber_scheduler_kernel_sleep(scheduler, RB_INT2NUM(0));
}