public HttpRequest form(final Map<?, ?> values) throws HttpRequestException {
    return form(values, CHARSET_UTF8);
  }
Write the values in the map as form data to the request body
<p>
The pairs specified will be URL-encoded in UTF-8 and sent with the
'application/x-www-form-urlencoded' content-type

@param values
@return this request
@throws HttpRequestException
lib/src/main/java/com/github/kevinsawicki/http/HttpRequest.java