Butler stream servers can generate client address.

logdog/client/butler/streamserver/localclient/local.go

 // Copyright 2016 The LUCI Authors. All rights reserved.
 // Use of this source code is governed under the Apache License, Version 2.0
 // that can be found in the LICENSE file.
 
-package streamclient
+package localclient
 
 import (
         "io"
 
         "github.com/luci/luci-go/logdog/client/butler"
+        "github.com/luci/luci-go/logdog/client/butlerlib/streamclient"
         "github.com/luci/luci-go/logdog/client/butlerlib/streamproto"
 )
 
 // localClient is a Client implementation that is directly bound to a Butler
 // instance.
 type localClient struct {
         *butler.Butler
 }
 
-// NewLocal creates a new Client instance bound to a local Butler instance. This
+var _ streamclient.Client = (*localClient)(nil)
+
+// New creates a new Client instance bound to a local Butler instance. This
 // sidesteps the need for an actual server socket and negotiation protocol and
 // directly registers streams via Butler API calls.
 //
 // Internally, the Stream uses an io.PipeWriter and io.PipeReader to ferry
 // data from the Stream's owner to the Butler.
-func NewLocal(b *butler.Butler) Client {
+func New(b *butler.Butler) streamclient.Client {
         return &localClient{b}
 }
 
-func (c *localClient) NewStream(f streamproto.Flags) (s Stream, err error) {
+func (c *localClient) NewStream(f streamproto.Flags) (s streamclient.Stream, err error) {
         pr, pw := io.Pipe()
         defer func() {
                 if err != nil {
                         pr.Close()
                         pw.Close()
                 }
         }()
 
         props := f.Properties()
-        stream := streamImpl{
+        stream := streamclient.BaseStream{
                 WriteCloser: pw,
-                props:       props,
+                P:           props,
         }
 
         // Add the Stream to the Butler.
         if err = c.AddStream(pr, props); err != nil {
                 return
         }
         return &stream, nil
 }