yield

fn yield(ev: *Evented, maybe_ready_fiber: ?*Fiber, pending_task: SwitchMessage.PendingTask) void {
    const thread: *Thread = .current();
    const ready_context = if (maybe_ready_fiber orelse ev.findReadyFiber(thread)) |ready_fiber|
        &ready_fiber.context
    else
        &thread.idle_context;
    const message: SwitchMessage = .{
        .contexts = .{
            .old = thread.current_context,
            .new = ready_context,
        },
        .pending_task = pending_task,
    };
    contextSwitch(&message).handle(ev);
}