httpcache

type RoundTripper struct {
	// Transport is the next RoundTripper in the chain. It is used for cache
	// misses and requests that bypass the cache. If nil, http.DefaultTransport
	// is used.
	Transport http.RoundTripper

	// DefaultCacheTTL defines how long an otherwise cacheable response is
	// considered fresh when no expiration time can be derived from its HTTP
	// headers. A non-positive value prevents storing such responses.
	DefaultCacheTTL time.Duration

	// UncacheableVaryHeaders lists request field names for which a response must
	// not be stored when the origin names one of them in Vary. The fields are not
	// ignored: ignoring an origin-provided Vary field would permit an incorrect
	// cache hit. This option is useful for volatile fields such as Signature,
	// Signature-Input or traceparent.
	UncacheableVaryHeaders []string
}