code: public static Part<String> text(String name, String value) {
          // the text part do not set content type
          return new Part<>(name, null, value, null, null, (body, out, charset) -> {
              OutputStreamWriter writer = new OutputStreamWriter(out, Objects2.elvis(charset, ISO_8859_1));
              writer.write(body);
              writer.flush();
          });
      }
docs: Create a text multi-part field.
  This return a part equivalent to &lt;input type="text" /&gt; field in multi part form.