The Main RX Thread that runs the client.consumer() call used to
parse packets as soon as it got them. This lead to an iffecient
strategy for listen and acquire packets as fast as possible.
The APRSDRXThread now gets the raw packet from the client and
shoves it on the packet_queue. The other threads that are looking
for packets on the packet_queue will parse the raw packet with
aprslib. This allows us to capture packets as quickly as we can,
and then process those packets in the secondary threads.
This prevents a bottleneck capturing packets.
