code: @SuppressWarnings("unchecked")
      protected final <T extends AmazonWebServiceRequest> T beforeMarshalling(
              T request) {
  
          T local = request;
          for (RequestHandler2 handler : requestHandler2s) {
              local = (T) handler.beforeMarshalling(local);
          }
          return local;
      }
docs: Runs the {@code beforeMarshalling} method of any
  {@code RequestHandler2}s associated with this client.
  
  @param request the request passed in from the user
  @return the (possibly different) request to marshal