I am using the AUD module to stream music from soundcloud to play in my game. The streaming works fine. However, when I press spacebar to change songs, the game still gets caught up. The threading works. It does everything in a separate thread from the game. I was able to isolate the issue to line 90 of the script: soundcloud.py, where it actually plays the music with handle.play().
Here is the blend to try it: Space Game 2018-4-15.blend (1.87 MB)
Controls are W, S, A, D to fly, and Spacebar to change songs.