Function appendVaryHeader

server/utils.go:169–176

appendVaryHeader appends the given key to the `Vary` header.

(header http.Header, key string)

// appendVaryHeader appends the given key to the `Vary` header.
func appendVaryHeader(header http.Header, key string) {
	vary := header.Get("Vary")
	if vary == "" {
		header.Set("Vary", key)
	} else {
		header.Set("Vary", vary+", "+key)
	}
}

// concatBytes concatenates two byte slices.
func concatBytes(a, b []byte) []byte {