E.g. a server accepts a connection, then spawn a child to handle it.
The server wants to close the socket to reclaim fd in the process,
but the child still needs to communicate with the client.

>From: Takashi Kato <xxxxxx@ymail.com>
Subject: Re: Last call
Date: Sun, 30 Jun 2013 11:30:36 +0200

> I'll add the following sentence to socket-close;
>
> The procedure should not shutdown the given socket. To shutdown a
> socket, socket-shutdown should be called explicitly.
>
> This is my curiosity. I think most of platforms free fd when close(2)
> is called and means the given socket fd will be invalid. What would be
> the happy case that socket-close doesn't automatically shutdown the
> socket?
>
>
> _/_/
> Takashi Kato
> E-mail: xxxxxx@ymail.com