protected HttpRequest startPart() throws IOException {
    if (!multipart) {
      multipart = true;
      contentType(CONTENT_TYPE_MULTIPART).openOutput();
      output.write("--" + BOUNDARY + CRLF);
    } else
      output.write(CRLF + "--" + BOUNDARY + CRLF);
    return this;
  }
Start part of a multipart

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