Butler stream servers can generate client address.

logdog/client/butlerlib/streamclient/client.go

Index: logdog/client/butlerlib/streamclient/client.go
diff --git a/logdog/client/butlerlib/streamclient/client.go b/logdog/client/butlerlib/streamclient/client.go
index da96e0521475151497ab924537cbd624dc8ec46d..87a92580cfcc986821e61cfd825dca84551b3976 100644
--- a/logdog/client/butlerlib/streamclient/client.go
+++ b/logdog/client/butlerlib/streamclient/client.go
@@ -70,9 +70,9 @@ func (c *clientImpl) NewStream(f streamproto.Flags) (Stream, error) {
 	}
 
 	// Perform the handshake: magic + size(data) + data.
-	s := &streamImpl{
+	s := &BaseStream{
 		WriteCloser: client,
-		props:       p,
+		P:           p,
 	}
 	if _, err := s.writeRaw(streamproto.ProtocolFrameHeaderMagic); err != nil {
 		return nil, fmt.Errorf("failed to write magic number: %s", err)