code: func TimeoutHandler(h httpx.Handler, dt time.Duration) httpx.Handler {
  	return &timeoutHandler{
  		handler: h,
  		dt:      dt,
  	}
  }
docs: // TimeoutHandler returns a Handler that runs h with the given time limit.
  //
  // The new Handler calls h.ServeHTTPContext to handle each request, but if a
  // call runs for longer than its time limit, the handler will return an
  // error that satisfies the timeoutError interface, to integrate with the
  // error middleware.
  //
  // After such a timeout, writes by h to its ResponseWriter will return
  // ErrHandlerTimeout.
  //
  // TimeoutHandler buffers all Handler writes to memory and does not
  // support the Hijacker or Flusher interfaces.
  //
  // NOTE This is a modified version of https://godoc.org/net/http#TimeoutHandler