docs: HystrixMetricsPublisherThreadPool getPublisherForThreadPool(HystrixThreadPoolKey threadPoolKey, HystrixThreadPoolMetrics metrics, HystrixThreadPoolProperties properties) {
          // attempt to retrieve from cache first
          HystrixMetricsPublisherThreadPool publisher = threadPoolPublishers.get(threadPoolKey.name());
          if (publisher != null) {
              return publisher;
          }
          // it doesn't exist so we need to create it
          publisher = HystrixPlugins.getInstance().getMetricsPublisher().getMetricsPublisherForThreadPool(threadPoolKey, metrics, properties);
          // attempt to store it (race other threads)
          HystrixMetricsPublisherThreadPool existing = threadPoolPublishers.putIfAbsent(threadPoolKey.name(), publisher);
          if (existing == null) {
              // we won the thread-race to store the instance we created so initialize it
              publisher.initialize();
              // done registering, return instance that got cached
              return publisher;
          } else {
              // we lost so return 'existing' and let the one we created be garbage collected
              // without calling initialize() on it
              return existing;
          }
      }