Correctly manage partial writes

mtglib/internal/obfuscated2/conn.go

@@ -10,11 +10,9 @@ type Conn struct {
 
 	Encryptor cipher.Stream
 	Decryptor cipher.Stream
-
-	writeBuf []byte
 }
 
-func (c *Conn) Read(p []byte) (int, error) {
+func (c Conn) Read(p []byte) (int, error) {
 	n, err := c.Conn.Read(p)
 	if err != nil {
 		return n, err // nolint: wrapcheck
@@ -25,9 +23,16 @@ func (c *Conn) Read(p []byte) (int, error) {
 	return n, nil
 }
 
-func (c *Conn) Write(p []byte) (int, error) {
-	c.writeBuf = append(c.writeBuf[:0], p...)
-	c.Encryptor.XORKeyStream(c.writeBuf, p)
+func (c Conn) Write(p []byte) (int, error) {
+	buf := acquireBytesBuffer()
+	defer releaseBytesBuffer(buf)
 
-	return c.Conn.Write(c.writeBuf)
+	buf.Write(p)
+
+	payload := buf.Bytes()
+	c.Encryptor.XORKeyStream(payload, payload)
+
+	n, err := buf.WriteTo(c.Conn)
+
+	return int(n), err // nolint: wrapcheck
 }