func NewTestTimeoutHandler(handler Handler, ctx context.Context) Handler {
	return &timeoutHandler{
		handler:     handler,
		testContext: ctx,
		// (no body)
	}
}

func ResetCachedEnvironment() {
	resetProxyConfig()
}

func (t *Transport) NumPendingRequestsForTesting() int {
	t.reqMu.Lock()
	defer t.reqMu.Unlock()
	return len(t.reqCanceler)
}

func (t *Transport) IdleConnKeysForTesting() (keys []string) {

func envProxyFunc() func(*url.URL) (*url.URL, error) {
	envProxyOnce.Do(func() {
		envProxyFuncValue = httpproxy.FromEnvironment().ProxyFunc()
	})
	return envProxyFuncValue
}

// resetProxyConfig is used by tests.
func resetProxyConfig() {
	envProxyOnce = sync.Once{}
	envProxyFuncValue = nil
}

func (t *Transport) connectMethodForRequest(treq *transportRequest) (cm connectMethod, err error) {