feat(p2p): support tcp protocol

gold/p2p/udp/init.go

@@ -1,17 +1,12 @@
 package udp
 
 import (
-	"errors"
 	"net"
 	"net/netip"
 
 	"github.com/fumiama/WireGold/gold/p2p"
 )
 
-var (
-	ErrEndpointTypeMistatch = errors.New("endpoint type mismatch")
-)
-
 func NewEndpoint(endpoint string, _ ...any) p2p.EndPoint {
 	return (*EndPoint)(net.UDPAddrFromAddrPort(
 		netip.MustParseAddrPort(endpoint),

gold/p2p/udp/udp.go

@@ -52,7 +52,7 @@ func (conn *Conn) ReadFromPeer(b []byte) (int, p2p.EndPoint, error) {
 func (conn *Conn) WriteToPeer(b []byte, ep p2p.EndPoint) (int, error) {
 	udpep, ok := ep.(*EndPoint)
 	if !ok {
-		return 0, ErrEndpointTypeMistatch
+		return 0, p2p.ErrEndpointTypeMistatch
 	}
 	return (*net.UDPConn)(conn).WriteTo(b, (*net.UDPAddr)(udpep))
 }