Will be needed if we want loolwsd to run on Windows. Then we will have one
process receiving the connections from WebSocket clients and sending the
accepted connection sockets to child processes thatr might be already running,
either because they have been "pre-forked", or because of a collaboration
scenario where new clients join a session working on a document.
But initially we will write this as if for Unix only, so development of this
migratory socket stuff is paused for now. (And it isn't even clear whether the
API design so far is a good idea and elegantly implementable.)
