env, _ := r.Context().Value(envVarsContextKey{}).(map[string]string)
	return env
}

// addFastCGIEnvToContext reports whether to include the FastCGI environment variable s
// in the http.Request.Context, accessible via ProcessEnv.
func addFastCGIEnvToContext(s string) bool {
	// Exclude things supported by net/http natively:
	switch s {
	case "CONTENT_LENGTH", "CONTENT_TYPE", "HTTPS",