Coro::Channel will round-robin between threads, nice...

coro_channel_multiget.pl

#!/usr/bin/env perl

use common::sense;
use Coro;

my $req = Coro::Channel->new;
my $rep = Coro::Channel->new;

sub start_worker {
  my $name = shift;

  async {
    while (1) {
      my $something = $req->get;
      $rep->put("$name: $something");
    }
  };
}

start_worker('first');
start_worker('second');

for (1 .. 100) {
  $req->put($_);
  say $rep->get;
}