net/http: add some examples

R=golang-dev, dsymonds, adg, rogpeppe, bradfitz
CC=golang-dev
https://golang.org/cl/5673052

src/pkg/net/http/example_test.go

+// Copyright 2012 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package http_test
+
+import (
+	"fmt"
+	"io/ioutil"
+	"log"
+	"net/http"
+)
+
+func ExampleHijacker() {
+	http.HandleFunc("/hijack", func(w http.ResponseWriter, r *http.Request) {
+		hj, ok := w.(http.Hijacker)
+		if !ok {
+			http.Error(w, "webserver doesn't support hijacking", http.StatusInternalServerError)
+			return
+		}
+		conn, bufrw, err := hj.Hijack()
+		if err != nil {
+			http.Error(w, err.Error(), http.StatusInternalServerError)
+			return
+		}
+		// Don't forget to close the connection:
+		defer conn.Close()
+		bufrw.WriteString("Now we're speaking raw TCP. Say hi: ")
+		bufrw.Flush()
+		s, err := bufrw.ReadString('\n')
+		if err != nil {
+			log.Printf("error reading string: %v", err)
+			return
+		}
+		fmt.Fprintf(bufrw, "You said: %q\nBye.\n", s)
+		bufrw.Flush()
+	})
+}
+
+func ExampleGet() {
+	res, err := http.Get("http://www.google.com/robots.txt")
+	if err != nil {
+		log.Fatal(err)
+	}
+	robots, err := ioutil.ReadAll(res.Body)
+	if err != nil {
+		log.Fatal(err)
+	}
+	res.Body.Close()
+	fmt.Printf("%s", robots)
+}