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