fix: eliminate pointer allocation warnings in sync.Pool usage (SA6002) (#36)

Refactor buffer management in TCP and UDP server handlers to avoid
unnecessary pointer allocations. Instead of taking addresses of slices
that are already pointers from sync.Pool, properly handle the pointer
types to resolve go-staticcheck SA6002 warnings.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-authored-by: Claude <noreply@anthropic.com>

Author: yuuki

server.go

@@ -28,7 +28,10 @@ var serveMsgBuf = sync.Pool{
 }
 
 var bufUDPPool = sync.Pool{
-	New: func() any { return make([]byte, UDPPacketSize) },
+	New: func() any {
+		buf := make([]byte, UDPPacketSize)
+		return &buf
+	},
 }
 
 type ServerConfig struct {
@@ -137,8 +140,9 @@ func (s *Server) serveTCP(ctx context.Context) error {
 func handleConnection(conn net.Conn) error {
 	defer conn.Close()
 
-	buf := *serveMsgBuf.Get().(*[]byte)
-	defer serveMsgBuf.Put(&buf)
+	bufPtr := serveMsgBuf.Get().(*[]byte)
+	defer serveMsgBuf.Put(bufPtr)
+	buf := *bufPtr
 
 	for {
 		n, err := conn.Read(buf)
@@ -202,10 +206,11 @@ func (s *Server) serveUDP(ctx context.Context) error {
 			}()
 
 			for {
-				msg := bufUDPPool.Get().([]byte)
+				msgPtr := bufUDPPool.Get().(*[]byte)
+				msg := *msgPtr
 				n, remoteAddr, err := ln.ReadFrom(msg)
 				if err != nil {
-					bufUDPPool.Put(msg)
+					bufUDPPool.Put(msgPtr)
 					select {
 					case <-ctx.Done():
 						return nil
@@ -215,14 +220,14 @@ func (s *Server) serveUDP(ctx context.Context) error {
 					continue
 				}
 
-				go func() {
-					defer bufUDPPool.Put(msg)
+				go func(msgPtr *[]byte, msg []byte) {
+					defer bufUDPPool.Put(msgPtr)
 					if _, err = ln.WriteTo(msg[:n], remoteAddr); err != nil {
 						slog.Error("UDP write error",
 							"remote_addr", remoteAddr,
 							"error", err)
 					}
-				}()
+				}(msgPtr, msg)
 			}
 		})
 	}