Expose remote audio track buffers (#268)

@@ -17,6 +17,31 @@
 package io.livekit.android.room.track
 
 import org.webrtc.AudioTrack
+import org.webrtc.AudioTrackSink
 import org.webrtc.RtpReceiver
 
-class RemoteAudioTrack(name: String, rtcTrack: AudioTrack, internal val receiver: RtpReceiver) : io.livekit.android.room.track.AudioTrack(name, rtcTrack)
+class RemoteAudioTrack(
+    name: String,
+    rtcTrack: AudioTrack,
+    internal val receiver: RtpReceiver
+) : io.livekit.android.room.track.AudioTrack(name, rtcTrack) {
+
+    /**
+     * Adds a sink that receives the audio bytes and related information
+     * for this audio track. Repeated calls using the same sink will
+     * only add the sink once.
+     *
+     * Implementations should copy the audio data into a local copy if they wish
+     * to use the data after this function returns.
+     */
+    fun addSink(sink: AudioTrackSink) {
+        rtcTrack.addSink(sink)
+    }
+
+    /**
+     * Removes a previously added sink.
+     */
+    fun removeSink(sink: AudioTrackSink) {
+        rtcTrack.removeSink(sink)
+    }
+}