Chore: Use buf.New() instead of buf.NewWithSize() (#5946)

https://github.com/XTLS/Xray-core/pull/5941#issuecomment-4252905907

https://github.com/XTLS/Xray-core/pull/5946#issuecomment-4253919073

proxy/hysteria/client.go

@@ -244,8 +244,11 @@ type UDPReader struct {
 
 func (r *UDPReader) ReadMultiBuffer() (buf.MultiBuffer, error) {
 	if r.firstMsg != nil {
-		buffer := buf.NewWithSize(int32(len(r.firstMsg.Data)))
-		buffer.Write(r.firstMsg.Data)
+		buffer := buf.New()
+		_, err := buffer.Write(r.firstMsg.Data)
+		if err != nil {
+			return nil, err
+		}
 		buffer.UDP = r.firstDest
 
 		r.firstMsg = nil
@@ -275,8 +278,11 @@ func (r *UDPReader) ReadMultiBuffer() (buf.MultiBuffer, error) {
 			continue
 		}
 
-		buffer := buf.NewWithSize(int32(len(dfMsg.Data)))
-		buffer.Write(dfMsg.Data)
+		buffer := buf.New()
+		if _, err := buffer.Write(dfMsg.Data); err != nil {
+			return nil, err
+		}
+
 		buffer.UDP = &dest
 
 		return buf.MultiBuffer{buffer}, nil

proxy/tun/udp_fullcone.go

@@ -103,8 +103,10 @@ func (c *udpConn) ReadMultiBuffer() (buf.MultiBuffer, error) {
 		return nil, io.EOF
 	}
 
-	b := buf.NewWithSize(int32(len(e.data)))
-	b.Write(e.data)
+	b := buf.New()
+	if _, err := b.Write(e.data); err != nil {
+		return nil, err
+	}
 	b.UDP = e.dest
 
 	return buf.MultiBuffer{b}, nil

proxy/wireguard/tun.go

@@ -350,8 +350,11 @@ func (c *udpConn) ReadMultiBuffer() (buf.MultiBuffer, error) {
 		return nil, io.EOF
 	}
 
-	b := buf.NewWithSize(int32(len(q.p)))
-	b.Write(q.p)
+	b := buf.New()
+	if _, err := b.Write(q.p); err != nil {
+		return nil, err
+	}
+
 	b.UDP = q.dest
 
 	return buf.MultiBuffer{b}, nil