The last sentence of the first paragraph in processing model background says

This means that a program that deals with audio only executes code from this callback, as any buffering between a rendering thread and the callback would naturally add latency or make the system less resilient to glitches.

The first part of the sentence talks about the callback, but the second part suddenly talks about buffering and latency. I don't see the connection here.

I also don't quite see how this should be rephrased.