use Pool to manage buffer

tls.go

@@ -374,14 +374,28 @@ func (c *Conn) getServerName() string {
 	return name
 }
 
+var bufPool = &sync.Pool{
+	New: func() interface{} {
+		return make([]byte, 16*1024)
+	},
+}
+
 // onDataReadCallback callback function for gnutls library want to read data from network
 //
 //export onDataReadCallback
 func onDataReadCallback(d unsafe.Pointer, cbuf *C.char, bufLen C.int) C.int {
 	//log.Println("read addr ", uintptr(d))
 	conn := (*Conn)(unsafe.Pointer((uintptr(d))))
-	buf := make([]byte, int(bufLen))
+
-	n, err := conn.c.Read(buf)
+	//buf := make([]byte, int(bufLen))
+	_length := int(bufLen)
+	buf := bufPool.Get().([]byte)
+	if len(buf) < _length {
+		buf = make([]byte, _length)
+	}
+	defer bufPool.Put(buf)
+
+	n, err := conn.c.Read(buf[:_length])
 	if err != nil {
 		//log.Println(err)
 		// 0 indicates connection termination