code: public <R> R download(String uri,
  			ContentHandler<BasicHttpResponse, R> handler)
  			throws RedmineException {
  		final HttpGet request = new HttpGet(uri);
  		return errorCheckingCommunicator.sendRequest(request, handler);
  	}
docs: Downloads a redmine content.
  
  @param uri
  target uri.
  @param handler
  content handler.
  @return handler result.
  @throws RedmineException
  if something goes wrong.