add iris websocket client side for Go and a simple chat example

Former-commit-id: af1c555b6b092a3d0484fee2e200fd8767d7239e

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

@@ -0,0 +1,58 @@
+package main
+
+import (
+	"bufio"
+	"fmt"
+	"os"
+
+	"github.com/kataras/iris/websocket"
+)
+
+const (
+	url    = "ws://localhost:8080/socket"
+	prompt = ">> "
+)
+
+/*
+How to run:
+Start the server, if it is not already started by executing `go run ../server/main.go`
+And open two or more terminal windows and start the clients:
+$ go run main.go
+>> hi!
+*/
+func main() {
+	conn, err := websocket.Dial(url, websocket.DefaultEvtMessageKey)
+	if err != nil {
+		panic(err)
+	}
+
+	conn.OnError(func(err error) {
+		fmt.Printf("error: %v", err)
+	})
+
+	conn.OnDisconnect(func() {
+		fmt.Println("Server was force-closed[see ../server/main.go#L19] this connection after 20 seconds, therefore I am disconnected.")
+		os.Exit(0)
+	})
+
+	conn.On("chat", func(message string) {
+		fmt.Printf("\n%s\n", message)
+	})
+
+	fmt.Println("Start by typing a message to send")
+	scanner := bufio.NewScanner(os.Stdin)
+	for {
+		fmt.Print(prompt)
+		if !scanner.Scan() || scanner.Err() != nil {
+			break
+		}
+		msgToSend := scanner.Text()
+		if msgToSend == "exit" {
+			break
+		}
+
+		conn.Emit("chat", msgToSend)
+	}
+
+	fmt.Println("Terminated.")
+}