code: public static Response delete(URI uri, Credentials credentials, Header[] requestHeaders)
          throws URISyntaxException, HttpException {
          return send(new HttpDelete(uri), credentials, requestHeaders);
      }
docs: Performs an HTTP DELETE on the given URI.
  Basic auth is used if both username and pw are not null.
  
  @param uri            The URI to connect to.
  @param credentials    Instance implementing {@link Credentials} interface holding a set of credentials
  @param requestHeaders Additional HTTP headers added to the request
  @return The HTTP response as Response object.
  @throws URISyntaxException
  @throws HttpException