I'm trying to playback audio from the microphone with a variable delay. Basically, an echo. I think I'm making a fundamental error though. I used the SpeakHere application as a template. I tried creating 2 queues: one record and one playback. Both are configured with the same format. I tried calling the enqueue on the opposite queue in the callback. In other words, in the recordingCallback, I enqueued the buffer into the playback queue. In the playbackCallback, I enqueued the buffer into the recording queue. Obviously, doesn't work. What is the best way to do what I'm trying to do?