private void closeAllClientCqs(CacheClientProxy proxy) {
    CqService cqService = proxy.getCache().getCqService();
    if (cqService != null) {
      final boolean isDebugEnabled = logger.isDebugEnabled(); // LocalizedMessage.create(
      try {
        if (isDebugEnabled) {
          logger.debug("CacheClientNotifier: Closing client CQs: {}", proxy);
        }
        cqService.closeClientCqs(proxy.getProxyID());
      } catch (CqException e1) {
        logger.warn("Unable to close CQs for the client: {}", proxy.getProxyID());
        if (isDebugEnabled) {
          logger.debug(e1.getMessage(), e1);
        }
      }
    }
  }
Returns an unmodifiable Collection of known {@code CacheClientProxy} instances. The
collection is not static so its contents may change.

@return the collection of known {@code CacheClientProxy} instances
geode-core/src/main/java/org/apache/geode/internal/cache/tier/sockets/CacheClientNotifier.java