private void complete(Exception e) {
    if (completed.compareAndSet(false, true)) {
      if (QuotaUtils.postProcessCharge(quotaChargeCallback)) {
        try {
          quotaChargeCallback.checkAndCharge(false, true);
        } catch (QuotaException quotaException) {
          LOGGER.info("Exception {} while charging quota for ttl operation", quotaException.toString());
        }
      }
      nonBlockingRouter.completeOperation(futureResult, callback, null, e, false);
    }
  }
Completes the batch operation
@param e the {@link Exception} that occurred (if any).
ambry-router/src/main/java/com/github/ambry/router/BatchOperationCallbackTracker.java