docs: private CompletableFuture<Void> bind(Bootstrap bootstrap) {
      CompletableFuture<Void> future = new CompletableFuture<>();
      int port = config.getPort() != null ? config.getPort() : address.port();
      if (config.getInterfaces().isEmpty()) {
        bind(bootstrap, Lists.newArrayList("0.0.0.0").iterator(), port, future);
      } else {
        bind(bootstrap, config.getInterfaces().iterator(), port, future);
      }
      return future;
    }