func (s EndpointState) String() string {
	switch s {
	case StateInitial:
		return "INITIAL"
	case StateBound:
		return "BOUND"
	case StateConnected:
		return "CONNECTING"
	case StateClosed:
		return "CLOSED"
	default:
		return "UNKNOWN"
	}
}
String implements fmt.Stringer.String.
package udp
import (
	"sync"
	"github.com/google/netstack/tcpip"
	"github.com/google/netstack/tcpip/buffer"
	"github.com/google/netstack/tcpip/header"
	"github.com/google/netstack/tcpip/iptables"
	"github.com/google/netstack/tcpip/stack"
	"github.com/google/netstack/waiter"
)
type udpPacket struct {
	udpPacketEntry
	senderAddress tcpip.FullAddress
	data          buffer.VectorisedView
	timestamp     int64
}
type EndpointState uint32
const (
	StateInitial EndpointState = iota
	StateBound
	StateConnected
	StateClosed
)