diff --git a/src/TestableIO.System.IO.Abstractions/FileSystemStream.cs b/src/TestableIO.System.IO.Abstractions/FileSystemStream.cs
index f72e92f8f..21e9a85d8 100644
--- a/src/TestableIO.System.IO.Abstractions/FileSystemStream.cs
+++ b/src/TestableIO.System.IO.Abstractions/FileSystemStream.cs
@@ -27,14 +27,14 @@ public override bool CanWrite
             => _stream.CanWrite;
 
         /// <inheritdoc cref="FileStream.IsAsync" />
-        public bool IsAsync { get; }
+        public virtual bool IsAsync { get; }
 
         /// <inheritdoc cref="Stream.Length" />
         public override long Length
             => _stream.Length;
 
         /// <inheritdoc cref="FileStream.Name" />
-        public string Name { get; }
+        public virtual string Name { get; }
 
         /// <inheritdoc cref="Stream.Position" />
         public override long Position