last unless ($rd_handles->count() || $wt_handles->count());
($rset, $wset) = IO::Select->select($rd_handles, $wt_handles, $er_handles, $timeout);
last unless ($rd_handles->count() || $wt_handles->count());
($rset, $wset) = IO::Select->select($rd_handles, $wt_handles, $er_handles, $timeout);