func NewMemCache(delegate http.RoundTripper, maxConcurrency int) http.RoundTripper {
	return NewFromCache(delegate, httpcache.NewMemoryCache(), maxConcurrency)
}
func NewMemCache(delegate http.RoundTripper, maxConcurrency int) http.RoundTripper {
	return NewFromCache(delegate, httpcache.NewMemoryCache(), maxConcurrency)
}
// NewMemCache creates a GitHub cache RoundTripper that is backed by a memory
// cache.