docs: protected long getContentLength(HttpServletRequest request) {
  		if (useServlet31) {
  			return request.getContentLengthLong();
  		}
  		String contentLengthHeader = request.getHeader(HttpHeaders.CONTENT_LENGTH);
  		if (contentLengthHeader != null) {
  			try {
  				return Long.parseLong(contentLengthHeader);
  			}
  			catch (NumberFormatException e) {
  			}
  		}
  		return request.getContentLength();
  	}