private static StringBuilder hms(StringBuilder b, int h, int m, int s) {
    int2(b, h);
    b.append(':');
    int2(b, m);
    b.append(':');
    int2(b, s);
    return b;
  }
Appends hour:minute:second to a buffer; assumes they are valid.
amoro-format-mixed/amoro-mixed-flink/amoro-mixed-flink-common/src/main/java/org/apache/amoro/flink/util/DateTimeUtils.java