backpressure on udp port required

[dch]

Under high load the refcounted binaries coming in on the socket may not be GCd fast enough. It should be pretty obvious when this is the case as the VM will run out of memory and die horribly.

Use https://github.com/ferd/pobox or https://github.com/jlouis/safetyvalve

[paulperegud]

There is no need to introduce explicit datagram drop to alleviate issue of inbox being unbounded. It's enough to switch socket (inet:setopts) from {active, true} to {active, 1} for processing. If datagrams will not be pulled fast enough BEAM or kernel themselves will start dropping datagrams.