sub once_init () {
my $self = fields::new('PublicInbox::EvCleanup');
my ($r, $w);
+
+ # This is a dummy pipe which is always writable so it can always
+ # fires in the next event loop iteration.
pipe($r, $w) or die "pipe: $!";
+ fcntl($w, 1031, 4096) if $^O eq 'linux'; # 1031: F_SETPIPE_SZ
$self->SUPER::new($w);
$self->{rd} = $r; # never read, since we never write..
$self;