use APR::Const     -compile => qw/SUCCESS/;
use APR::Brigade;
use APR::Bucket;
use APR::Status;
use APR::Error;
[...]
sub handler {
   [...]

   my $bb_in  = APR::Brigade->new($c->pool, $c->bucket_alloc);
   my $bb_out = APR::Brigade->new($c->pool, $c->bucket_alloc);
   while (1) {
      my $rc = $c->input_filters->get_brigade($bb_in, 
                           Apache2::Const::MODE_GETLINE);
      last if APR::Status::is_EOF($rc);
      die APR::Error::strerror($rc) unless $rc == 
                                     APR::Const::SUCCESS;

      my $last = 0;
      while (!$bb_in->is_empty) {
         my $b = $bb_in->first;
         $b->remove;
         if ($b->is_eos) {
            $bb_out->insert_tail($b);
            $last++;
            last;
         }
         if ($b->read(my $data)) {
            warn $data; # testing line
         }
         $bb_out->insert_tail($b);
      }
      if ($last) {
         $bb_out->insert_tail(APR::Bucket::flush_create($c->bucket_alloc));
         $c->output_filters->pass_brigade($bb_out);
         last;
      }
   }
   [...]