private <K> Map<K, QuotaLimiter> setLimiter(Map<K, QuotaLimiter> limiters, final K key,
    final Quotas quotas) {
    if (limiters == null) {
      limiters = new HashMap<>();
    }

    QuotaLimiter limiter =
      quotas.hasThrottle() ? QuotaLimiterFactory.fromThrottle(quotas.getThrottle()) : null;
    if (limiter != null && !limiter.isBypass()) {
      limiters.put(key, limiter);
    } else {
      limiters.remove(key);
    }
    return limiters;
  }
Add the quota information of the specified namespace. (This operation is part of the QuotaState
setup)
hbase-server/src/main/java/org/apache/hadoop/hbase/quotas/UserQuotaState.java