cookie.go
func (c *Cookie) CopyTo(src *Cookie) {
	c.Reset()
	c.key = append(c.key[:0], src.key...)
	c.value = append(c.value[:0], src.value...)
	c.expire = src.expire
	c.maxAge = src.maxAge
	c.domain = append(c.domain[:0], src.domain...)
	c.path = append(c.path[:0], src.path...)
	c.httpOnly = src.httpOnly
	c.secure = src.secure
	c.sameSite = src.sameSite
}
func (c *Cookie) CopyTo(src *Cookie) {
	c.Reset()
	c.key = append(c.key[:0], src.key...)
	c.value = append(c.value[:0], src.value...)
	c.expire = src.expire
	c.maxAge = src.maxAge
	c.domain = append(c.domain[:0], src.domain...)
	c.path = append(c.path[:0], src.path...)
	c.httpOnly = src.httpOnly
	c.secure = src.secure
	c.sameSite = src.sameSite
}
// CopyTo copies src cookie to c.