concurrent_steps_2.pl

Mojo::IOLoop->delay->steps(
  
  sub { ... },
  
  sub {
    my $delay = shift;
    Mojo::IOLoop->timer(3 => sub { $delay->pass(-s1) });
  },
  
  # concurrent steps
  [
    sub {
      my $delay = shift;
      my $s1    = shift;
      Mojo::IOLoop->timer(3 => sub { $delay->pass(-c1) });
    },
    sub {
      my $delay = shift;
      my $s1    = shift;
      Mojo::IOLoop->timer(3 => sub { $delay->pass(-c2) });
    },
    sub {
      my $delay = shift;
      my $s1    = shift;
      Mojo::IOLoop->timer(3 => sub { $delay->pass(-c3) });
    }
  ],
  
  # Called after 3 seconds
  sub {
    my ($delay, $c1, $c2, $c3) = @_;
    Mojo::IOLoop->timer(3 => $delay->begin);
  },
  
  sub { ... }
);