Markup file - added optional parameter to the constructor so we can c…

…hange the markup file over time

src/Framework/Framework/Hosting/MarkupFile.cs

@@ -67,11 +67,12 @@ public MarkupFile(string fileName, string fullPath)
             };
         }
 
-        public MarkupFile(string fileName, string fullPath, string contents)
+        public MarkupFile(string fileName, string fullPath, string contents, DateTime lastWriteDateTimeUtc = default)
         {
             FileName = fileName;
             FullPath = fullPath;
             ReadContent = () => contents;
+            LastWriteDateTimeUtc = lastWriteDateTimeUtc;
         }
 
         public override bool Equals(object? obj)