add ability to set voice target

gumble/audio.go

@@ -43,7 +43,11 @@ func (ab AudioBuffer) writeTo(client *Client, w io.Writer) (int64, error) {
 
 	// Create audio header
 	var header bytes.Buffer
-	formatTarget := byte(4)<<5 | byte(0)
+	var targetId int
+	if target := client.audioTarget; target != nil {
+		targetId = target.id
+	}
+	formatTarget := byte(4)<<5 | byte(targetId)
 	if err := header.WriteByte(formatTarget); err != nil {
 		return 0, err
 	}

gumble/client.go

@@ -73,6 +73,7 @@ type Client struct {
 
 	audioEncoder  *gopus.Encoder
 	audioSequence int
+	audioTarget   *VoiceTarget
 
 	end        chan bool
 	closeMutex sync.Mutex
@@ -102,6 +103,7 @@ func (c *Client) Connect() error {
 		encoder.SetVbr(false)
 		c.audioEncoder = encoder
 		c.audioSequence = 0
+		c.audioTarget = nil
 	}
 	if conn, err := tls.DialWithDialer(&c.config.Dialer, "tcp", c.config.Address, &c.config.TlsConfig); err != nil {
 		c.audioEncoder = nil
@@ -292,6 +294,12 @@ func (c *Client) ContextActions() ContextActions {
 	return c.contextActions
 }
 
+// SetVoiceTarget sets to whom transmitted audio will be sent. The VoiceTarget
+// must have already been sent to the server for targeting to work correctly.
+func (c *Client) SetVoiceTarget(target *VoiceTarget) {
+	c.audioTarget = target
+}
+
 // Send will send a message to the server.
 func (c *Client) Send(message Message) error {
 	c.sendMutex.Lock()