public Map<ClientProxyMembershipID, Integer> getClientQueueSizes() {
    Map<ClientProxyMembershipID, Integer> queueSizes = new HashMap<>();
    for (CacheClientProxy proxy : _clientProxies.values()) {
      queueSizes.put(proxy.getProxyID(), proxy.getQueueSize());
    }
    return queueSizes;
  }
Returns (possibly stale) map of queue sizes for all clients notified by this server.

@return map with CacheClientProxy as key, and Integer as a value
geode-core/src/main/java/org/apache/geode/internal/cache/tier/sockets/CacheClientNotifier.java