@Override
        public Boolean put(String key, Boolean value) {
            // grab the previous result, so we can still satisfy the method signature of Map
            Boolean previous = LuckPermsPermissionAttachment.this.perms.get(key);

            // proxy the call back through the PermissionAttachment instance
            setPermission(key, value);

            // return the previous value
            return previous;
        }
A fake map to be injected into the superclass. This implementation simply
proxies calls back to this attachment instance.

Some (clever/dumb??) plugins attempt to modify attachment permissions using reflection
to get around the slow bukkit behaviour in the base PermissionAttachment implementation.

An instance of this map is injected into the super instance so these plugins continue
to work with LuckPerms.
bukkit/src/main/java/me/lucko/luckperms/bukkit/inject/permissible/LuckPermsPermissionAttachment.java