code: func (ctx *RequestCtx) TimeoutErrorWithResponse(resp *Response) {
  	respCopy := &Response{}
  	resp.CopyTo(respCopy)
  	ctx.timeoutResponse = respCopy
  }
docs: // TimeoutErrorWithResponse marks the ctx as timed out and sends the given
  // response to the client.
  //
  // All ctx modifications after TimeoutErrorWithResponse call are ignored.
  //
  // TimeoutErrorWithResponse MUST be called before returning from RequestHandler
  // if there are references to ctx and/or its members in other goroutines remain.
  //
  // Usage of this function is discouraged. Prefer eliminating ctx references
  // from pending goroutines instead of using this function.