{
  my $buffer = "";
  sub _print {
    my @args = @_;
    $buffer .= sprintf shift @args, @args;
    return;
   }

   sub _flush {
     my $content = $buffer;
     $buffer = "";
     local $| = 1;
     print $content;
   }
}

_print($cgi->header( -type => .... ));
......
_flus();