Use a more simple tranport protocol for the realtime data. Use a piece
of shared memory and a socket where we use a 1byte read/write to trigger
remote actions. Also use a ringbuffer for events.
Enable the header metadata so that we have timestamps again.
Rework allocation in the link a little. Reuse previously allocated
buffers when possible. Keep track of where the buffers was allocated.
Make some more convenience functions to initialize buffer headers. Make
it so that we move allocations to the app.
Make some helpers to make memfd memory in pinos now that we will be able
to do all allocation there.
Bring back the channel object. Making a node and port on the client side
was rather awkward because of the async nature of many methods. It feels
better to have a specific communication channel object to interface with
a server side port.
Use port activate/deactivate to start/stop streams
Remove links from the ports. We let other objects install a callback on
the port to receive and route buffers.
