@Override
  default Collection<ResourcePermission> getRequiredPermissions(String regionName) {
    return Collections.singletonList(ResourcePermissions.ALL);
  }
InternalFunction do require ResourcePermissions.ALL so that it only allows super users to
invoke from Clients. So don't override this in implementations.
geode-core/src/main/java/org/apache/geode/internal/cache/execute/InternalFunction.java