docs: @ExperimentalApi("https://github.com/grpc/grpc-java/issues/1869")
    @SuppressWarnings("unchecked")
    public <T> T getOption(Key<T> key) {
      Preconditions.checkNotNull(key, "key");
      for (int i = 0; i < customOptions.length; i++) {
        if (key.equals(customOptions[i][0])) {
          return (T) customOptions[i][1];
        }
      }
      return key.defaultValue;
    }