How to decouple Depth framerate from RGB?

[Lorne Covington]

I have tried editing the OpenNI2 driver to turn off registration and not
enable the RGB stream, but the depth stream still runs at 15FPS not 30.

Where in libfreenect2 is this association made? Are these transfers
tied together down at the USB level?

Unfortunately a 15FPS frame rate on the depth makes it unusable for most
interactive applications, it introduces just too much latency.

Thanks folks!

- Lorne