Johan's observation is correct. Network.listenOn is alreay fixed but
Network.Socket.listen, which Warp relies on, is not fixed yet. I will
try to fix it. When the next version of the network library will be
released, the problem will disappear, I hope.

We should consider how we fix this. Right now N.S.listen just wraps the underlying system call. Is that the right place to set socket options? Perhaps we should set them when creating the socket instead?

-- Johan