func (u *Unsubscribe) String() string {
	var topics []string
	for _, t := range u.Topics {
		topics = append(topics, fmt.Sprintf("%q", t))
	}
	return fmt.Sprintf("<Unsubscribe Topics=[%s]>", strings.Join(topics, ", "))
}
String returns a string representation of the packet.
package packet
import (
	"fmt"
	"strings"
)
type Unsubscribe struct {
	Topics []string
	ID ID
}
func NewUnsubscribe() *Unsubscribe {
	return &Unsubscribe{}
}
func (u *Unsubscribe) Type() Type {
	return UNSUBSCRIBE
}