From liukan@360.cn

Two scenarios will render the following code "useless".

my $p = Promise.new;
IO​::Notification.watch-path( 'a' ).act​: { .event.say; }
await $p;

1. If file or directory 'a' does not exist, no Failure.
2. If 'a' initially exists, then removed/moved, then a new 'a' is created, the new 'a' no longer has the identity of the initial file/dir that was 'a'. Subsequent behavior is same as that of 1.

Lacking a .stat method, and a way of notifying removal, there isn't a good way to track the original target, and figure out nature of the change.

- kan