Close handshake not working correctly

[nhooyr]

Was reported to me on reddit by @skwair.

Reproducible example:

package main

import (
	"context"
	"fmt"
	"time"

	"nhooyr.io/websocket"
)

func main() {
	ctx, cancel := context.WithTimeout(context.Background(), time.Minute)
	defer cancel()

	c, _, err := websocket.Dial(ctx, "ws://localhost:3333", nil)
	if err != nil {
		// ...
	}
	defer c.Close(websocket.StatusInternalError, "the sky is falling")

	go func() {
		_, _, err := c.Read(context.TODO())
		fmt.Println("failed to read:", err)
	}()

	fmt.Println(c.Close(websocket.StatusNormalClosure, ""))
}

package main

import (
	"context"
	"log"
	"net/http"
	"time"

	"nhooyr.io/websocket"
	"nhooyr.io/websocket/wsjson"
)

func main() {
	http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
		c, err := websocket.Accept(w, r, nil)
		if err != nil {
			// ...
		}
		defer c.Close(websocket.StatusInternalError, "the sky is falling")

		ctx, cancel := context.WithTimeout(r.Context(), time.Second*10)
		defer cancel()

		var v interface{}
		err = wsjson.Read(ctx, c, &v)
		if err != nil {
			log.Println(err)
			return
			// ...
		}

		log.Printf("received: %v", v)

		c.Close(websocket.StatusNormalClosure, "")
	})

	http.ListenAndServe(":3333", nil)
}

Definitely some sort of race condition as it works normally sometimes for me but interestingly enough the client side Read in the other goroutine returns a nil error.

Will fix ASAP.