header.go
func (h *ResponseHeader) Cookie(cookie *Cookie) bool {
	v := peekArgBytes(h.cookies, cookie.Key())
	if v == nil {
		return false
	}
	cookie.ParseBytes(v)
	return true
}
func (h *ResponseHeader) Cookie(cookie *Cookie) bool {
	v := peekArgBytes(h.cookies, cookie.Key())
	if v == nil {
		return false
	}
	cookie.ParseBytes(v)
	return true
}
// Cookie fills cookie for the given cookie.Key.
//
// Returns false if cookie with the given cookie.Key is missing.