code: public Response saveAttachment(InputStream in, String name, String contentType) {
          return saveAttachment(in, name, contentType, null, null);
      }
docs: Saves an attachment to a new document with a generated <tt>UUID</tt> as the document id.
  <p>To retrieve an attachment, see {@link #find(String)}.
  
  @param in          The {@link InputStream} holding the binary data.
  @param name        The attachment name.
  @param contentType The attachment "Content-Type".
  @return {@link Response}