close without callback

[aep]

trying to close a socket inside accept has some confusing api usage.
it's not entirely clear what the callback is for and how to use it correctly

    var server_conn: ?xev.TCP = null;
    server.accept(&loop, &c_accept, ?xev.TCP, &server_conn, (struct {
        fn callback(
            _: ?*?xev.TCP,
            loop2: *xev.Loop,
            _: *xev.Completion,
            r: xev.AcceptError!xev.TCP,
        ) xev.CallbackAction {
            std.log.info("accepted", .{});

           var sock = r catch unreachable;
            var c_why: xev.Completion = undefined;
            defer sock.close(loop2, &c_why, void, null, closeCallback);



            return .rearm;
        }
    }).callback);

[1] aep@MacBookAir: ~/work/zig/httpd zig build && ./zig-out/bin/httpd
info: accepted
thread 1006309 panic: switch on corrupt value
/Users/aep/.cache/zig/p/12208fa7b1c9723ab1e97548595cda3810e881e17e8a7d367eaab75b3408848277d5/src/backend/kqueue.zig:889:17: 0x10013d64f in stop_completion (httpd)
        switch (c.op) {
                ^
/Users/aep/.cache/zig/p/12208fa7b1c9723ab1e97548595cda3810e881e17e8a7d367eaab75b3408848277d5/src/backend/kqueue.zig:180:50: 0x10013a48b in submit (httpd)
                    .dead => self.stop_completion(c),
                                                 ^
/Users/aep/.cache/zig/p/12208fa7b1c9723ab1e97548595cda3810e881e17e8a7d367eaab75b3408848277d5/src/backend/kqueue.zig:333:24: 0x10013ee7b in tick (httpd)
        try self.submit();
                       ^
/Users/aep/.cache/zig/p/12208fa7b1c9723ab1e97548595cda3810e881e17e8a7d367eaab75b3408848277d5/src/backend/kqueue.zig:264:62: 0x100140bd3 in run (httpd)
            .until_done => while (!self.done()) try self.tick(1),
                                                             ^
/Users/aep/work/zig/httpd/src/main.zig:43:17: 0x100140fef in main (httpd)
    try loop.run(.until_done);
                ^
/Users/aep/zig/0.13.0/files/lib/std/start.zig:524:37: 0x10014165f in main (httpd)
            const result = root.main() catch |err| {
                                    ^
???:?:?: 0x196894273 in ??? (???)
???:?:?: 0x0 in ??? (???)