void updateThrottlerDesiredRate(String jobType, double newDesiredRatePerSec) {
    Throttler throttler = throttlers.get(jobType);
    if (throttler != null) {
      throttler.updateDesiredRatePerSecond(newDesiredRatePerSec);
    }
  }
Update desired rate of a job type.
@param jobType the type of the job requesting an I/O slice.
@param newDesiredRatePerSec the newDesiredRatePerSec.
ambry-store/src/main/java/com/github/ambry/store/DiskIOScheduler.java