const (
	Accept        = "Accept"
	Authorization = "Authorization"
	ContentType   = "Content-Type"
	ContentLength = "Content-Length"
)

var (
	// Monoid is a [M.Monoid] to concatenate [http.Header] maps
	Monoid = RG.UnionMonoid[http.Header](A.Semigroup[string]())

	// AtValues is a [L.Lens] that focusses on the values of a header
	AtValues = F.Flow2(
		textproto.CanonicalMIMEHeaderKey,
		LRG.AtRecord[http.Header, []string],
	)

	// AtValue is a [L.Lens] that focusses on first value of a header
	AtValue = F.Flow2(
		AtValues,
		composeHead,
	)
)