The data source implementation of a ma_pcm_rb could possibly return a
frame count of 0 which would in turn result in
ma_data_source_read_pcm_frames() returning MA_AT_END which does not
make sense for a ring buffer since it has no notion of an end.
This example captures data from the microphone using the low-level API
and then plays back the data through the engine. The intermediary data
source is a ring buffer.
David Reid