. . .
# My box o' global connections
my @cnx;
. . .
$server->establish($fh)->cb(
   sub {
      my $connection = eval { shift->recv };

      # Add new connection to the box
      push @cnx, $connection;

      # Remove connection when it closes
      $connection->on(finish => sub {
         @cnx = grep { $_ ne $connection } @cnx;
      }
      . . .
   }
);
. . .
sub send_global_message {
   my $msg = shift;
   for my $c (@cnx) {
      $c->send($msg);
   }
}