Fix tlsfragment fallback writeAndWaitAck

common/tlsfragment/conn.go

@@ -109,6 +109,9 @@ func (c *Conn) Write(b []byte) (n int, err error) {
 						if err != nil {
 							return
 						}
+						if i != len(splitIndexes) {
+							time.Sleep(c.fallbackDelay)
+						}
 					}
 				}
 			}

common/tlsfragment/wait_stub.go

@@ -9,6 +9,10 @@ import (
 )
 
 func writeAndWaitAck(ctx context.Context, conn *net.TCPConn, payload []byte, fallbackDelay time.Duration) error {
+	_, err := conn.Write(payload)
+	if err != nil {
+		return err
+	}
 	time.Sleep(fallbackDelay)
 	return nil
 }

common/tlsfragment/wait_windows.go

@@ -16,6 +16,9 @@ func writeAndWaitAck(ctx context.Context, conn *net.TCPConn, payload []byte, fal
 	err := winiphlpapi.WriteAndWaitAck(ctx, conn, payload)
 	if err != nil {
 		if errors.Is(err, windows.ERROR_ACCESS_DENIED) {
+			if _, err := conn.Write(payload); err != nil {
+				return err
+			}
 			time.Sleep(fallbackDelay)
 			return nil
 		}