const extraCookieLength = 110
	var b strings.Builder
	b.Grow(len(c.Name) + len(c.Value) + len(c.Domain) + len(c.Path) + extraCookieLength)
	b.WriteString(c.Name)
	b.WriteRune('=')
	b.WriteString(sanitizeCookieValue(c.Value, c.Quoted))

	if len(c.Path) > 0 {
		b.WriteString("; Path=")
		b.WriteString(sanitizeCookiePath(c.Path))
	}
	if len(c.Domain) > 0 {
		if validCookieDomain(c.Domain) {

		{"a ", false, `"a "`},
		{"a,z", false, `"a,z"`},
		{",z", false, `",z"`},
		{"a,", false, `"a,"`},
	}
	for _, tt := range tests {
		if got := sanitizeCookieValue(tt.in, tt.quoted); got != tt.want {
			t.Errorf("sanitizeCookieValue(%q) = %q; want %q", tt.in, got, tt.want)
		}
	}

	if got, sub := logbuf.String(), "dropping invalid bytes"; !strings.Contains(got, sub) {

// AddCookie only sanitizes c's name and value, and does not sanitize
// a Cookie header already present in the request.
func (r *Request) AddCookie(c *Cookie) {
	s := fmt.Sprintf("%s=%s", sanitizeCookieName(c.Name), sanitizeCookieValue(c.Value, c.Quoted))
	if c := r.Header.Get("Cookie"); c != "" {
		r.Header.Set("Cookie", c+"; "+s)
	} else {
		r.Header.Set("Cookie", s)
	}
}