concurrent_steps_proposal.pl

Mojo::IOLoop->delay->steps(
  
  named_serial_step => sub { ... },
  
  named_serial_step2 => sub {
    my $delay = shift;
    $something ? $delay->pass : $delay->skip_to('named_serial_step3');
  },
  
  {
    named_concurrent_step1 => sub {
      my $delay = shift;
      Mojo::IOLoop->timer(3 => sub { $delay->pass(-c1) });
    },
    named_concurrent_step2 => sub {
      my $delay = shift;
      Mojo::IOLoop->timer(3 => sub { $delay->pass(-c2) });
    },
    named_concurrent_step3 => sub {
      my $delay = shift;
      Mojo::IOLoop->timer(3 => sub { $delay->pass(-c3) });
    }
  },
  
  # Called after 3 seconds
  named_serial_step3 => sub {
    my ($delay, $c1, $c2, $c3) = @_;
    Mojo::IOLoop->timer(3 => $delay->begin);
  },
  
  named_serial_step4 => sub { ... }
);