Do not call wait_readable with a closed fd in TrioEventLoop
Do not call wait_readable with a closed fd in TrioEventLoop

Fixes #378

wardi/urwid,inducer/urwid,urwid/urwid,inducer/urwid,wardi/urwid,urwid/urwid,urwid/urwid,wardi/urwid,inducer/urwid