Audiotrack.setVolume not working on Android (WebRTC)

I'm using Google WebRTC implementation on Android (org.webrtc:google-webrtc:1.0.30039). Everything works fine, but I can't adjust microphone sensitivity, i.e. the volume of local audio track. Setting volume to 0.0 or to 1.0 doesn't change anything, the level is always the same (I assume 100%).

    audioTrack = peerConnectionFactory.createAudioTrack("101", audioSource);
    audioTrack.setEnabled(true);
    audioTrack.setVolume(0);

How to adjust the signal volume?