docs: private Set<ConnectionKey> getStaleConnectionKeys() {
  
          Map<ConnectionKey, StatefulRedisConnection<K, V>> map = new ConcurrentHashMap<>();
          connectionProvider.forEach(map::put);
  
          Set<ConnectionKey> stale = new HashSet<>();
  
          for (ConnectionKey connectionKey : map.keySet()) {
  
              if (connectionKey.host != null && findNodeByHostAndPort(knownNodes, connectionKey.host, connectionKey.port) != null) {
                  continue;
              }
              stale.add(connectionKey);
          }
          return stale;
      }