From de4628f45098cb9735197cbd435fd6da82b447a4 Mon Sep 17 00:00:00 2001
From: James Jackson-South <james_south@hotmail.com>
Date: Mon, 22 Jan 2018 20:58:15 +1100
Subject: [PATCH] Add perf explanation

---
 src/Umbraco.Core/ObjectExtensions.cs | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/src/Umbraco.Core/ObjectExtensions.cs b/src/Umbraco.Core/ObjectExtensions.cs
index e4c9d94eba..1e3c75ee6d 100644
--- a/src/Umbraco.Core/ObjectExtensions.cs
+++ b/src/Umbraco.Core/ObjectExtensions.cs
@@ -718,8 +718,10 @@ namespace Umbraco.Core
             if (AssignableTypeCache.TryGetValue(key, out bool canConvert))
             {
                 return canConvert;
-            }
-
+            }
+
+            // "object is" is faster than "Type.IsAssignableFrom.
+            // We can use it to very quickly determine whether true/false
             if (input is IConvertible && target.IsAssignableFrom(source))
             {
                 return AssignableTypeCache[key] = true;