presto-hive/src/main/java/io/prestosql/plugin/hive/metastore/thrift/ThriftHiveMetastoreClient.java/ThriftHiveMetastoreClient/listRoleGrants
class ThriftHiveMetastoreClient:    @Override
    public List<RolePrincipalGrant> listRoleGrants(String principalName, PrincipalType principalType)
            throws TException
    {
        GetRoleGrantsForPrincipalRequest request = new GetRoleGrantsForPrincipalRequest(principalName, principalType);
        GetRoleGrantsForPrincipalResponse resp = client.get_role_grants_for_principal(request);
        return ImmutableList.copyOf(resp.getPrincipalGrants());
    }