Removed MediaFileSystemExtensions and just added the methods to the MediaFileSystem which are more discoverable.

Added Code Annotations to all file system classes pointing to the new #U4-1156 tracking item to publicize.

src/Umbraco.Core/IO/PhysicalFileSystem.cs

@@ -4,9 +4,12 @@ using System.IO;
 using System.Linq;
 using System.Text;
 using System.Web;
+using Umbraco.Core.CodeAnnotations;
 
 namespace Umbraco.Core.IO
 {
+
+	[UmbracoExperimentalFeature("http://issues.umbraco.org/issue/U4-1156", "Will be declared public after 4.10")]
     internal class PhysicalFileSystem : IFileSystem
     {
         private readonly string _rootPath;