@Override
    public boolean equals(@Nullable Object o) {
      if (o instanceof StringCharsetFunnel) {
        StringCharsetFunnel funnel = (StringCharsetFunnel) o;
        return this.charset.equals(funnel.charset);
      }
      return false;
    }

    @Override
    public int hashCode() {
      return StringCharsetFunnel.class.hashCode() ^ charset.hashCode();
    }

    Object writeReplace() {