mojo_async.pl

#!/usr/bin/env perl

use strict;
use warnings;
use Data::Dumper;

use List::Util qw/reduce/;

use Mojolicious::Lite;

use Mojo::UserAgent;
use Mojo::IOLoop;

get '/async' => sub {
    my $self = shift;

    my @res = ();

    my $ua = $self->ua;

    $ua->get( 'http://google.com' => cb( \@res ) );
    $ua->get( 'http://ya.ru' => cb( \@res ) );

    $ua->ioloop->start;

    return $self->render( text => join "\n", @res );
};

app->start;

sub cb {
    my $output = shift;
    return sub {
        my ( $ua, $tx ) = @_;
        push @$output, $tx->req->url->to_string;
        $ua->ioloop->stop if @$output >= 2;
    };
}