code review 6483061: net/http/httputil: fix race in DumpRequestOut

src/pkg/net/http/httputil/dump.go

 // Copyright 2009 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 httputil
 
 import (
         "bufio"
         "bytes"
         "fmt"
@@ skipping 71 matching lines @@
         pr, pw := io.Pipe()
         dr := &delegateReader{c: make(chan io.Reader)}
         // Wait for the request before replying with a dummy response:
         go func() {
                 http.ReadRequest(bufio.NewReader(pr))
                 dr.c <- strings.NewReader("HTTP/1.1 204 No Content\r\n\r\n")
         }()
 
         t := &http.Transport{
                 Dial: func(net, addr string) (net.Conn, error) {
-                        return &dumpConn{io.MultiWriter(pw, &buf), dr}, nil
+                        return &dumpConn{io.MultiWriter(&buf, pw), dr}, nil
                 },
         }
 
         _, err := t.RoundTrip(reqSend)
 
         req.Body = save
         if err != nil {
                 return nil, err
         }
         return buf.Bytes(), nil
@@ skipping 117 matching lines @@
         }
         err = resp.Write(&b)
         resp.Body = save
         resp.ContentLength = savecl
         if err != nil {
                 return
         }
         dump = b.Bytes()
         return
 }