Or you can process the document as it arrives (second
       $ua->request() argument is a code reference):

         use LWP::UserAgent;
         $ua = LWP::UserAgent->new;
         $URL = 'ftp://ftp.unit.no/pub/rfc/rfc-index.txt';

         my $expected_length;
         my $bytes_received = 0;
         my $res =
            $ua->request(HTTP::Request->new(GET => $URL),
                      sub {
                          my($chunk, $res) = @_;
                          $bytes_received += length($chunk);
                          unless (defined $expected_length) {
                             $expected_length = $res->content_length || 0;
                          }
                          if ($expected_length) {
                               printf STDERR "%d%% - ",
                                         100 * $bytes_received / $expected_length;
                          }
                          print STDERR "$bytes_received bytes received\n";

                          # XXX Should really do something with the chunk itself
                          # print $chunk;
                      });
          print $res->status_line, "\n";