deinit

pub fn deinit(ev: *Evented) void {
    const main_fiber: *Fiber = @ptrCast(&ev.main_fiber_buffer);
    assert(Thread.current().currentFiber() == main_fiber);
    const active_threads = @atomicLoad(u32, &ev.threads.active, .acquire);
    for (ev.threads.allocated[0..active_threads]) |*thread| {
        const ready_fiber = @atomicLoad(?*Fiber, &thread.ready_queue, .monotonic);
        assert(ready_fiber == null or ready_fiber == Fiber.finished); // pending async
    }
    ev.yield(null, .exit);
    ev.null_fd.close();
    ev.random_fd.close();
    const allocated_ptr: [*]align(@alignOf(Thread)) u8 = @ptrCast(@alignCast(ev.threads.allocated.ptr));
    const idle_stack_end_offset = std.mem.alignForward(
        usize,
        ev.threads.allocated.len * @sizeOf(Thread) + idle_stack_size,
        std.heap.pageSize(),
    );
    for (ev.threads.allocated[1..active_threads]) |*thread| thread.thread.join();
    for (ev.threads.allocated[0..active_threads]) |*thread| thread.deinit(ev.backing_allocator);
    assert(active_threads == ev.threads.active); // spawned threads while there was no pending async?
    ev.backing_allocator.free(allocated_ptr[0..idle_stack_end_offset]);
    ev.* = undefined;
}