Fix asset file.

Directory.Build.props

@@ -11,7 +11,7 @@
     <PackageProjectUrl>https://github.com/squidex/squidex</PackageProjectUrl>
     <PublishRepositoryUrl>true</PublishRepositoryUrl>
     <SymbolPackageFormat>snupkg</SymbolPackageFormat>
-    <Version>6.4.0</Version>
+    <Version>6.4.1</Version>
   </PropertyGroup>
 
   <PropertyGroup Condition="'$(GITHUB_ACTIONS)' == 'true'">

assets/Squidex.Assets/AssetFile.cs

@@ -11,22 +11,25 @@ namespace Squidex.Assets;
 
 public abstract class AssetFile : IDisposable, IAsyncDisposable
 {
-    public string FileName { get; }
+    private readonly string fileName;
+    private readonly string mimeType;
+    private readonly long fileSize;
 
-    public string MimeType { get; }
+    public virtual string FileName => fileName;
 
-    public long FileSize { get; }
+    public virtual string MimeType => mimeType;
+
+    public virtual long FileSize => fileSize;
 
     protected AssetFile(string fileName, string mimeType, long fileSize)
     {
         Guard.NotNullOrEmpty(fileName, nameof(fileName));
         Guard.NotNullOrEmpty(mimeType, nameof(mimeType));
         Guard.GreaterEquals(fileSize, 0, nameof(fileSize));
 
-        FileName = fileName;
-        FileSize = fileSize;
-
-        MimeType = mimeType;
+        this.fileName = fileName;
+        this.fileSize = fileSize;
+        this.mimeType = mimeType;
     }
 
     public virtual void Dispose()

assets/Squidex.Assets/TempAssetFile.cs

@@ -11,6 +11,8 @@ public sealed class TempAssetFile : AssetFile
 {
     private readonly Stream stream;
 
+    public override long FileSize => stream.Length;
+
     public static TempAssetFile Create(AssetFile source)
     {
         return new TempAssetFile(source.FileName, source.MimeType, source.FileSize);