io-server-async and run on mac

fail.p6

use v6;

sub MAIN($port=5000) {
    react {
        whenever IO::Socket::Async.listen('127.0.0.1', $port) -> $conn {
            run 'ls'; # process exits at here.
            await $conn.print("yo");
            $conn.close();
        }
    }
}

This script exits at 'run' method on mac.
It returns "yo" on linux.