public MultiPartUtility formField(String name, String value) {
   buffer.appendString("--" + BOUNDARY).appendString(LINE_FEED);
   buffer
       .appendString("Content-Disposition: form-data; name=\"" + name + "\"")
       .appendString(LINE_FEED);
   buffer.appendString("Content-Type: text/plain; charset=" + charset).appendString(LINE_FEED);
   buffer.appendString(LINE_FEED);
   buffer.appendString(value).appendString(LINE_FEED);
   return this;
 }
 public MultiPartUtility attachmentHead(String fileName) {
   buffer.appendString("--" + BOUNDARY).appendString(LINE_FEED);
   buffer
       .appendString(
           "Content-Disposition: form-data; name=\""
               + attachmentName
               + "\"; filename=\""
               + fileName
               + "\"")
       .appendString(LINE_FEED);
   buffer
       .appendString("Content-Type: " + URLConnection.guessContentTypeFromName(fileName))
       .appendString(LINE_FEED);
   buffer.appendString("Content-Transfer-Encoding: binary").appendString(LINE_FEED);
   buffer.appendString(LINE_FEED);
   return this;
 }