default double getQuotaValue() {
    return (double) getQuotaRuntime() / (System.currentTimeMillis() - getStartTime());
  }
Quota value is calculated by the total millisecond running time of all tasks in the process
divided by the total millisecond from the start time to the current time. It is used to
evaluate the actual runtime concurrence of the process.

@return the quota value of the process.
amoro-common/src/main/java/org/apache/amoro/process/ProcessState.java