diff --git a/src/ThreadRunner.cs b/src/ThreadRunner.cs
index 964e0cb..415bd12 100644
--- a/src/ThreadRunner.cs
+++ b/src/ThreadRunner.cs
@@ -1,3 +1,6 @@
+using System;
+using System.Threading;
+
 namespace DCFApixels.DragonECS
 {
     internal static class ThreadRunner