diff --git a/cs/src/core/Utilities/Utility.cs b/cs/src/core/Utilities/Utility.cs
index fab72aa36..34aa94ccd 100644
--- a/cs/src/core/Utilities/Utility.cs
+++ b/cs/src/core/Utilities/Utility.cs
@@ -4,6 +4,7 @@
 using System;
 using System.Runtime.InteropServices;
 using System.Runtime.CompilerServices;
+using System.Threading;
 
 namespace FASTER.core
 {
@@ -231,6 +232,7 @@ public static bool MonotonicUpdate(ref long variable, long newValue, out long ol
             } while (Interlocked.CompareExchange(ref variable, newValue, oldValue) != oldValue);
             return true;
         }
+
         /// <summary>
         /// Updates the variable to newValue only if the current value is smaller than the new value.
         /// </summary>