Merge "Update doc for aaudio data callback."

 * in the streams current data format to the audioData buffer.

 *

 * For an input stream, this function should read and process numFrames of data

 * from the audioData buffer.

 * from the audioData buffer. The data in the audioData buffer must not be modified

 * directly. Instead, it should be copied to another buffer before doing any modification.

 * In many cases, writing to the audioData buffer of an input stream will result in a

 * native exception.

 *

 * The audio data is passed through the buffer. So do NOT call AAudioStream_read() or

 * AAudioStream_write() on the stream that is making the callback.