import "net/http/internal/ascii"
func EqualFold(s, t string) bool
EqualFold is strings.EqualFold, ASCII only. It reports whether s and t are equal, ASCII-case-insensitively.
func Is(s string) bool
Is returns whether s is ASCII.
func IsPrint(s string) bool
IsPrint returns whether s is ASCII and printable according to https://tools.ietf.org/html/rfc20#section-4.2.
func ToLower(s string) (lower string, ok bool)
ToLower returns the lowercase version of s if s is ASCII and printable.