code: func (f *Forwarder) catchAll(ctx *authContext, w http.ResponseWriter, req *http.Request) (interface{}, error) {
  	sess, err := f.getOrCreateClusterSession(*ctx)
  	if err != nil {
  		return nil, trace.Wrap(err)
  	}
  	if err := f.setupForwardingHeaders(ctx, sess, req); err != nil {
  		return nil, trace.Wrap(err)
  	}
  	sess.forwarder.ServeHTTP(w, req)
  	return nil, nil
  }
docs: // catchAll forwards all HTTP requests to the target k8s API server