use threads::lite;
my $factory = threads::line->new( -threads => 10 ); #reserve 10 threads

my $x_thr = $factory->create( \&doX, \@Xargs, \%optional_configs );
my $y_thr = $factory->create( \&doY, \@Yargs );

##</code><code>##

sub _default_thread {
   my $thr_id = shift;
   if (defined $s_coderef[$thr_id] && ref $s_coderef[$thr_id] eq 'CODE') {
      $s_coderef[$thr_id]->(@{ $s_param[$thr_id] });
      $s_coderef[$thr_id] = undef;
   }
   else { sleep(1) }
}