protected static String stringFromMillis(long millis) {
    StringBuilder buf = new StringBuilder();
    long hours = millis / (60 * 60 * 1000);
    long rem = (millis % (60 * 60 * 1000));
    long minutes = rem / (60 * 1000);
    rem = rem % (60 * 1000);
    long seconds = rem / 1000;
    long milliseconds = rem % 1000;

    if (hours != 0) {
      buf.append(hours);
      buf.append(hours > 1 ? "hrs, " : "hr, ");
    }
    if (minutes != 0) {
      buf.append(minutes);
      buf.append(minutes > 1 ? "mins, " : "min, ");
    }
    if (seconds != 0) {
      buf.append(seconds);
      buf.append("sec, ");
    }
    buf.append(milliseconds);
    buf.append("ms");
    return buf.toString();
  }
Describe the throttling result. TODO: At some point this will be handled on the client side to
prevent operation to go on the server if the waitInterval is greater than the one got as result
of this exception.
hbase-client/src/main/java/org/apache/hadoop/hbase/quotas/RpcThrottlingException.java