Butler stream servers can generate client address.

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

Index: logdog/client/butler/streamserver/localclient/local.go
diff --git a/logdog/client/butlerlib/streamclient/local.go b/logdog/client/butler/streamserver/localclient/local.go
similarity index 70%
rename from logdog/client/butlerlib/streamclient/local.go
rename to logdog/client/butler/streamserver/localclient/local.go
index cbfda96251f90de577c8fcbde44b460390bb2b5f..481e2bafd736db8ac9d0c88be3dc4d4d00cd17c6 100644
--- a/logdog/client/butlerlib/streamclient/local.go
+++ b/logdog/client/butler/streamserver/localclient/local.go
@@ -2,12 +2,13 @@
 // 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"
 )
 
@@ -17,17 +18,19 @@ 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 {
@@ -37,9 +40,9 @@ func (c *localClient) NewStream(f streamproto.Flags) (s Stream, err error) {
 	}()
 
 	props := f.Properties()
-	stream := streamImpl{
+	stream := streamclient.BaseStream{
 		WriteCloser: pw,
-		props:       props,
+		P:           props,
 	}
 
 	// Add the Stream to the Butler.