// exception is HTTP status code 101 (Switching Protocols), which is
// considered a terminal status and returned by [Transport.RoundTrip]. To see the
// ignored 1xx responses, use the httptrace trace package's
// ClientTrace.Got1xxResponse.
//
// Transport only retries a request upon encountering a network error
// if the connection has been already been used successfully and if the

		// seeing a 1xx response.
		ctx, cancel := context.WithCancel(context.Background())
		defer cancel()
		ctx = httptrace.WithClientTrace(ctx, &httptrace.ClientTrace{
			Got1xxResponse: func(code int, header textproto.MIMEHeader) error {
				cancel()
				return nil
			},
		})

		req, _ := http.NewRequestWithContext(ctx, "GET", "http://go.dev/", nil)