inotify failing to watch a directory

inotify.go

package main

import (
	"fmt"
	"os"
	"time"

	"golang.org/x/exp/inotify"
)

func main() {
	watcher, err := inotify.NewWatcher()
	if err != nil {
		panic(err)
	}

	watchdir := "/tmp/watchtest"

	err = os.Mkdir(watchdir, 0644)
	if err != nil {
		if err != os.ErrExist {
			panic(err)
		}
	}
	defer os.RemoveAll(watchdir)

	err = watcher.AddWatch(watchdir, inotify.IN_CREATE+inotify.IN_DELETE+inotify.IN_ISDIR)
	if err != nil {
		panic(err)
	}

	go func() {
		for {
			select {
			case ev := <-watcher.Event:
				switch ev.Mask {
				case inotify.IN_CREATE + inotify.IN_ISDIR:
					fmt.Println("DIR CREATED: " + ev.Name)
					watcher.AddWatch(ev.Name, inotify.IN_DELETE+inotify.IN_CREATE+inotify.IN_ISDIR)
				case inotify.IN_DELETE + inotify.IN_ISDIR:
					fmt.Println("DIR DELETED: " + ev.Name)
					watcher.RemoveWatch(ev.Name)
				}
			case err := <-watcher.Error:
				fmt.Println("error:", err)
			}
		}
	}()

	for i := 0; i < 5; i++ {
		err = os.Mkdir(watchdir+"/test", 0644)
		if err != nil {
			panic(err)
		}

		time.Sleep(time.Millisecond * 1)

		err = os.Mkdir(watchdir+"/test/1", 0644)
		if err != nil {
			panic(err)
		}

		time.Sleep(time.Millisecond * 1)

		err = os.RemoveAll(watchdir + "/test")
		if err != nil {
			panic(err)
		}

		time.Sleep(time.Millisecond * 1)
	}
}