func (c *Cookie) SetKey(key string) {
	c.key = append(c.key[:0], key...)
}
func (c *Cookie) SetKey(key string) {
	c.key = append(c.key[:0], key...)
}
func ( c * Cookie ) SetKey ( key string ) { c . key = append ( c . key [ : 0 ] , key ... ) }
// SetKey sets cookie name.
SetKey sets cookie name .