# the data:
    sub uvh_loop_get_data(Loop --> Pointer[void]) is native(&find-uvdata) { * }
    sub uvh_loop_set_data(Loop,    Pointer[void]) is native(&find-uvdata) { * }

    method data() is rw {
        Proxy.new(
            FETCH => method () { uvh_loop_get_data(self); },
            STORE => method (Pointer[void] $value) { uvh_loop_set_data(self, $value); }
        );
    }

# test code
my $ptr = nativecast(Pointer[void], $loop);
dd $ptr;
$loop.data = $ptr;