* To read bytes, use ma_decoder_read_bytes().
* To seek bytes, use ma_decoder_seek_bytes().
* The read pointer is now tracked in the ma_decoder object. You can use
  this to move back to a prior position.

The default low-latency buffer size is now 10 milliseconds per period.
The default conservative buffer size is now 100 milliseconds per
period.

This simplifies the callback since the client does not need to worry
about silencing parts of the buffer that are not filled, such as the
end of a song or whatnot.