curry.cs

      Fn<ImmutableArray<KeyValuePair<string, string>>.Builder, Act < string, string>> createAppend =
        builder => (key, value) => {
          qs.append(key, value);
          builder.Add(F.kv(key, value));
        };
      var appendTag = createAppend(tags);
      var appendExtra = createAppend(extras);