Example of first write succeeding, but second write failing

main.go

package main

import (
	"fmt"
	"net/http"
	"time"

	"github.com/gorilla/websocket"
)

func main() {
	done := make(chan struct{}, 1)
	http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
		conn, _ := (&websocket.Upgrader{}).Upgrade(w, r, nil)
		conn.Close()
		done <- struct{}{}
	})
	go http.ListenAndServe(":10080", nil)
	time.Sleep(100 * time.Millisecond)

	conn, _, _ := websocket.DefaultDialer.Dial("ws://localhost:10080", nil)
	<-done
	time.Sleep(1 * time.Second)
	err := conn.WriteMessage(websocket.BinaryMessage, []byte("message"))
	if err != nil {
		panic(fmt.Sprintf("first write failed: %s", err.Error()))
	}
	fmt.Println("first write succeeded")

	err = conn.WriteMessage(websocket.BinaryMessage, []byte("message"))
	if err != nil {
		fmt.Printf("second write failed: %s\n", err.Error())
	}

	conn, _, _ = websocket.DefaultDialer.Dial("ws://localhost:10080", nil)
	<-done
	time.Sleep(1 * time.Second)
	writer, err := conn.NextWriter(websocket.BinaryMessage)
	if err != nil {
		fmt.Printf("first NextWriter failed: %s\n", err.Error())
	}

	n, err := writer.Write([]byte("message"))
	if err != nil {
		fmt.Printf("writer write failed: %s\n", err.Error())
	}
	fmt.Printf("writer wrote %d bytes\n", n)

	err = writer.Close()
	if err != nil {
		fmt.Printf("writer close failed: %s\n", err.Error())
	}
	fmt.Println("writer closed successfully")

	writer, err = conn.NextWriter(websocket.BinaryMessage)
	if err != nil {
		fmt.Printf("second wrtier failed: %s\n", err.Error())
	}
	fmt.Println("Got second writer.")

	_, _, err = conn.ReadMessage()
	if err != nil {
		fmt.Printf("first read failed: %s\n", err.Error())
	}
	_, _, err = conn.NextReader()
	if err != nil {
		fmt.Printf("first nextreader failed: %s\n", err.Error())
	}

}