docs: @Override
      public List<MetricFamilySamples> collect() {
          final GaugeMetricFamily stats = new GaugeMetricFamily(
                  name,
                  "Bulkhead Stats",
                  asList("name", "param"));
  
          for (Bulkhead bulkhead : bulkheadsSupplier.get()) {
  
              final Bulkhead.Metrics metrics = bulkhead.getMetrics();
  
              stats.addMetric(
                      asList(bulkhead.getName(), "available_concurrent_calls"),
                      metrics.getAvailableConcurrentCalls());
          }
  
          return singletonList(stats);
      }