presto-hive/src/main/java/io/prestosql/plugin/hive/security/SqlStandardAccessControlMetadata.java/SqlStandardAccessControlMetadata/listRoleGrants
class SqlStandardAccessControlMetadata:    @Override
    public Set<RoleGrant> listRoleGrants(ConnectorSession session, HivePrincipal principal)
    {
        return ImmutableSet.copyOf(metastore.listRoleGrants(principal));
    }