presto-hive/src/main/java/io/prestosql/plugin/hive/metastore/SemiTransactionalHiveMetastore.java/SemiTransactionalHiveMetastore/listRoleGrants
class SemiTransactionalHiveMetastore:    public synchronized Set<RoleGrant> listRoleGrants(HivePrincipal principal)
    {
        checkReadable();
        return delegate.listRoleGrants(principal);
    }