Restore ability to transmit in stereo.

client.go

@@ -108,7 +108,7 @@ func (b *Barnard) connect(reconnect bool) bool {
 		}
 	})
 
-	// Initialize stereo encoder for file playback, reusing the one built for
+	// Initialize stereo encoder for two-channel capture and file playback, reusing the one built for
 	// the previous connection rather than allocating another.
 	if b.stereoEncoder == nil {
 		b.stereoEncoder = opus.NewStereoEncoder()