private void maybeStopTrackingWaitForChannelDataTime() {
    if (startTimeForChannelDataAvailabilityMs != 0) {
      // this is the first point in time since the last wait that data became available in the channel.
      waitTimeForChannelDataAvailabilityMs += time.milliseconds() - startTimeForChannelDataAvailabilityMs;
      startTimeForChannelDataAvailabilityMs = 0;
    }
  }
Called whenever data becomes available in the channel.
ambry-router/src/main/java/com/github/ambry/router/PutOperation.java