public static String formatTimestampMillis(int time, int precision) {
    final StringBuilder buf = new StringBuilder(8 + (precision > 0 ? precision + 1 : 0));
    formatTimestampMillis(buf, time, precision);
    return buf.toString();
  }
Parses a fraction, multiplying the first character by {@code multiplier}, the second character
by {@code multiplier / 10}, the third character by {@code multiplier / 100}, and so forth.

<p>For example, {@code parseFraction("1234", 100)} yields {@code 123}.
amoro-format-mixed/amoro-mixed-flink/amoro-mixed-flink-common/src/main/java/org/apache/amoro/flink/util/DateTimeUtils.java