Fix resource handling in udpflow sample
Thanks to comments by Felipe @meteficha Lessa in the pull-request
review. Now strace does show the expected close calls.
See: #69 (comment)
Rework udpflow sample to use a connected socket
Add finalizers to udpflow example
Yet, according to strace, they don't seem to work...
Add udpflow sample application
This is a very simple application which forks 2 threads, one sending
messages to a port, another one receiving (and discarding) them.
The application should be built using the threaded RTS. Consider using
2 capabilities upon execution (+RTS -N2).