read.pl

use Mojo::Base -strict;
use Mojo::UserAgent;
use Mojo::Util 'sha1_sum';

my $ua = Mojo::UserAgent->new;

# Decorate every transaction in "start" event
$ua->on(start => sub {
  my ($ua, $tx) = @_;

  # First "read" event to show chunk size
  $tx->res->content->on(read => sub {
    my ($content, $chunk) = @_;
    say 'Chunk size: ', length($chunk), ' bytes';
  });

  # Second "read" event to generate SHA1 sum for chunk
  $tx->res->content->on(read => sub {
    my ($content, $chunk) = @_;
    say 'Chunk SHA1: ', sha1_sum($chunk);
  });
});

# Normal request
my $tx = $ua->get('mojolicio.us');
say 'Content size: ', length($tx->res->body), ' bytes';
say 'Content SHA1: ', sha1_sum($tx->res->body);