Make it possible to pass custom memory to the builder so that it can
construct packets directly into specified memory and avoid allocs.
Remove GError and GSocketControlMessage in the buffer API to make it
possible to use other (rt-safe) API later.
Make an object for a processing node.
Implement a sink node. Make it possible to implement Sink and Source
interfaces to provide input/output from the node.
Improve pinosdepay to track fds and handle format changes.