presto-main/src/main/java/io/prestosql/operator/scalar/FormatFunction.java/FormatFunction/toLocalDateTime
class FormatFunction:    private static LocalDateTime toLocalDateTime(ConnectorSession session, long value)
    {
        Instant instant = Instant.ofEpochMilli(value);
        if (session.isLegacyTimestamp()) {
            ZoneId zoneId = ZoneId.of(session.getTimeZoneKey().getId());
            return LocalDateTime.ofInstant(instant, zoneId);
        }
        return LocalDateTime.ofInstant(instant, ZoneOffset.UTC);
    }