presto-hive/src/main/java/io/prestosql/plugin/hive/authentication/DirectHdfsAuthentication.java/DirectHdfsAuthentication/doAs
class DirectHdfsAuthentication:    @Override
    public <R, E extends Exception> R doAs(String user, GenericExceptionAction<R, E> action)
            throws E
    {
        return executeActionInDoAs(hadoopAuthentication.getUserGroupInformation(), action);
    }