code: func (h *Error) ServeHTTPContext(ctx context.Context, w http.ResponseWriter, r *http.Request) error {
  	err := h.handler.ServeHTTPContext(ctx, w, r)
  
  	if err != nil {
  		f := h.ErrorHandler
  		if f == nil {
  			f = DefaultErrorHandler
  		}
  
  		f(ctx, err, w, r)
  	}
  
  	// Pass the error up for any other middleware to use.
  	return err
  }
docs: // ServeHTTPContext implements the httpx.Handler interface.