On Ctrl-D, shutdown outgoing socket but keep reading from incoming socket until it shuts down as well

[jwodder]

The outgoing socket can apparently be shut down with SinkExt::close(), which (for Framed) calls AsyncWriteExt::shutdown().

See also: the -N and -q options of OpenBSD's netcat(1):

• -N — Shutdown the socket after EOF on input
• -q <seconds> — After EOF on input, wait <seconds> and then quit; implies -N