Bring back C# sample logging!

samples/CSharpWpf/App.xaml.cs

@@ -5,6 +5,8 @@ namespace CSharpWpf
 {
     public partial class App : Application
     {
+        public static MemoryLogger Log { get; private set; } = new();
+
         // Since WPF has an "automatic" Program.Main, we need to create our own.
         // In order for this to work, you must also add the following to your .csproj:
         // <StartupObject>CSharpWpf.App</StartupObject>
@@ -15,6 +17,7 @@ namespace CSharpWpf
                 // It's important to Run() the VelopackApp as early as possible in app startup.
                 VelopackApp.Build()
                     .OnFirstRun((v) => { /* Your first run code here */ })
+                    .SetLogger(Log)
                     .Run();
 
                 // We can now launch the WPF application as normal.