is MojoX::Run really asynchronous

In looking at the SYNOPSIS example for MojoX::Run

 # create async executor SINGLETON object
 my $mojox_run = MojoX::Run->singleton();
 
 # simple usage
 my $pid = $mojox_run->spawn(
        cmd => "ping -W 2 -c 5 host.example.org",
        exit_cb => sub {
                my ($pid, $res) = @_;
                print "Ping finished with exit status $res->{exit_val}
+.\n";
                print "\tSTDOUT:\n$res->{stdout}\n";
                print "\tSTDERR:\n$res->{stderr}\n";
        }
 );
 # check for injuries
 unless ($pid) {
        print "Command startup failed: ", $mojox_run->error(), "\n";
 }
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I'm wondering what is asynchronous about its usage. The reason that I say this is because of the line unless ($pid) which to me implies that line does not execute until the exit callback fires - there is no other way for $pid to be bound until then

synchronous shell usage

I like the API for MojoX::Run quite a bit. It makes the calling of shell commands succinct, handling the capture of STDERR and STDOUT, etc. Is there a similar tool on CPAN for synchronous shell usage?