+ *
+ * latency is compensated by adding it to the timecode to
+ * be generated. e.g. if the signal will reach the output in
+ * N samples time from now, generate the timecode for (now + N).
+ *
+ * sample-sync is achieved by further calculating the difference
+ * between the timecode and the session-transport and offsetting the
+ * buffer.
+ *
+ * The timecode is generated directly in the Session process callback
+ * using _transport_sample (which is the audible frame at the
+ * output).