code: public static void appendEpochMicros(StringBuilder buf, long timeMicros) {
          buf.append(dateTimeFormatter.format(Instant.ofEpochMilli(TimeUnit.MICROSECONDS.toMillis(timeMicros))))
             .append('(').append(timeMicros).append(')');
      }
docs: Formats the given epoch time in microseconds to typical human-readable format
  "yyyy-MM-dd'T'HH_mm:ss.SSSX" and appends it to the specified {@link StringBuilder}.