LivoxProto1: Document UDP demuxer purpose & use cases

Also fix bug in transient resource transfer from continuation
to Device object.

commonLibs/livoxProto1/udpCommandDemuxer.h

@@ -20,6 +20,17 @@ namespace comms {
  * This class listens on the command port (65000) for incoming UDP datagrams
  * from Livox devices and routes them to the appropriate Device based on
  * the source IP address.
+ *
+ * The reason we need a whole class for this is because we use the same port
+ * numbers for all connected devices, so we have no way to distinguish between
+ * devices except based on the devices' IP addrs. Since all commands are sent
+ * over UDP, our sockets don't have built-in binding to a specific source IP.
+ *
+ * So we need to discriminate between source IPs manually, and demultiplex
+ * the dgrams received from different devices manually.
+ *
+ * We'll prolly also have to do the same thing for point cloud and IMU data, so
+ * we'll prolly end up renaming this class to UdpResponseDemuxer.
  */
 class UdpCommandDemuxer
 {