fcgi_accept_request function is supposed to call a FastCGI implementation's
on_accept hook when entering an "accepting" stage (that is right before
calling "accept"). This hook implementation (fpm_request_accepting) updates
a worker state to an "accepting" state which is effectively an "Idle" state,
and updates counters on the scoreboard of the corresponding pool (idle++,
active--).
But this is not done when listening for client connections on a named pipe on
Windows platform. In that case a combination of
ConnectNamedPipe/WaitForSingleObject is used (to be able to catch in_shutdown
as far as I understand), but it is nonetheless functionally equivalent to
"accept" call. Also by not calling on_hook neither a worker's state is updated
to "accepting" state nor scoreboard counters are updated.