draft-nx-audswapper

init
while true
 if audout does not contain buffer1
  decode to buffer1, then schedule it
 if audout does not contain buffer2
  decode to buffer2, then schedule it.
 wait for buffer finish. make sure timeout is a reasonable time for 3 buffers worth of audio to play in, just in case.

-- Modified from Ghabry's code

instance->LockMutex();
for (int index = 0; index < 2; index++) {
 // If the function errors, we assume the buffer isn't there. Might want to change this.
 bool contain = true;
 // Either one or none of the buffers are playing, in which case this appends the buffers that aren't playing,
 //  or two buffers are playing due to some sort of freak accident, 
 audoutContainsAudioOutBuffer(source_buffer[index], &contain);
 if (!contain) {
  instance->Decode((uint8_t*)source_buffer[index]->buffer, buf_size);
  audoutAppendAudioOutBuffer(source_buffer[index]);
 }
}
instance->UnlockMutex();
// we don't do anything with the result values, but they have to be non-null
// Apparently, the timeout is documented as waiting until all buffers are finished.
// If this is true, comment this out, add a sleep for 1/2 buffer time
audoutWaitPlayFinish(&released_buffer, &released_count, U64_MAX);