add websocket client stress test, passed and update the vendors (this commit fixes the https://github.com/kataras/iris/issues/1178 and https://github.com/kataras/iris/issues/1173)

Former-commit-id: 74ccd8f4bf60a71f1eb0e34149a6f19de95a9148

_examples/websocket/go-client-stress-test/client/main.go

@@ -0,0 +1,85 @@
+package main
+
+import (
+	"bufio"
+	"fmt"
+	"math/rand"
+	"os"
+	"sync"
+	"time"
+
+	"github.com/kataras/iris/websocket"
+)
+
+var (
+	url = "ws://localhost:8080/socket"
+	f   *os.File
+)
+
+const totalClients = 1200
+
+func main() {
+	var err error
+	f, err = os.Open("./test.data")
+	if err != nil {
+		panic(err)
+	}
+	defer f.Close()
+
+	wg := new(sync.WaitGroup)
+	for i := 0; i < totalClients/2; i++ {
+		wg.Add(1)
+		go connect(wg, 5*time.Second)
+	}
+
+	for i := 0; i < totalClients/2; i++ {
+		wg.Add(1)
+		waitTime := time.Duration(rand.Intn(10)) * time.Millisecond
+		time.Sleep(waitTime)
+		go connect(wg, 10*time.Second+waitTime)
+	}
+
+	wg.Wait()
+	fmt.Println("ALL OK.")
+	time.Sleep(5 * time.Second)
+}
+
+func connect(wg *sync.WaitGroup, alive time.Duration) {
+
+	c, err := websocket.Dial(url, websocket.ConnectionConfig{})
+	if err != nil {
+		panic(err)
+	}
+
+	c.OnError(func(err error) {
+		fmt.Printf("error: %v", err)
+	})
+
+	disconnected := false
+	c.OnDisconnect(func() {
+		fmt.Printf("I am disconnected after [%s].\n", alive)
+		disconnected = true
+	})
+
+	c.On("chat", func(message string) {
+		fmt.Printf("\n%s\n", message)
+	})
+
+	go func() {
+		time.Sleep(alive)
+		if err := c.Disconnect(); err != nil {
+			panic(err)
+		}
+
+		wg.Done()
+	}()
+
+	scanner := bufio.NewScanner(f)
+	for !disconnected {
+		if !scanner.Scan() || scanner.Err() != nil {
+			break
+		}
+
+		c.Emit("chat", scanner.Text())
+	}
+}