Added old console sample to test diy message pump.

samples/WinConsole32/Program.cs

@@ -0,0 +1,106 @@
+using NTwain;
+using NTwain.Data;
+using System.Diagnostics;
+
+namespace WinConsole32
+{
+  internal class Program
+  {
+    static async Task Main(string[] args)
+    {
+      var libVer = FileVersionInfo.GetVersionInfo(typeof(TwainAppSession).Assembly.Location).ProductVersion;
+      Console.WriteLine($"Console sample {(TWPlatform.Is32bit ? " 32bit" : " 64bit")} on NTwain {libVer}");
+
+      MessagePumpThread pump = new MessagePumpThread();
+      TwainAppSession session = new TwainAppSession(Environment.ProcessPath!);
+
+      session.StateChanged += Session_StateChanged;
+      session.SourceDisabled += Session_SourceDisabled1;
+      session.Transferred += Session_Transferred;
+
+      var sts = await pump.AttachAsync(session);
+
+      if (sts.IsSuccess)
+      {
+        Console.WriteLine("Available data sources:");
+
+        TW_IDENTITY_LEGACY firstSrc = default;
+        foreach (var src in session.GetSources())
+        {
+          if (!firstSrc.HasValue) firstSrc = src;
+          Console.WriteLine($"\t{src}");
+        }
+        Console.WriteLine();
+
+        var defaultSrc = session.DefaultSource;
+        Console.WriteLine($"Default data source = {defaultSrc}");
+        Console.WriteLine();
+
+        session.ShowUserSelect();
+        Console.WriteLine($"Selected data source = {session.DefaultSource}");
+        Console.WriteLine();
+
+        var targetSrc = defaultSrc.HasValue ? defaultSrc : firstSrc;
+
+        if (targetSrc.HasValue)
+        {
+          TestThisSource(session, targetSrc);
+        }
+        else
+        {
+          Console.WriteLine("No data source to test.");
+          Console.WriteLine();
+        }
+
+        Console.WriteLine("---------------------------------------------");
+        Console.WriteLine("Test in progress, press Enter to stop testing");
+        Console.WriteLine("---------------------------------------------");
+        Console.ReadLine();
+        session.TryStepdown(STATE.S1);
+      }
+      else
+      {
+        Console.WriteLine("Failed to attach: " + sts);
+      }
+
+      Console.WriteLine("-------------------");
+      Console.WriteLine("Press Enter to exit");
+      Console.WriteLine("-------------------");
+      Console.ReadLine();
+    }
+
+    private static void Session_Transferred(TwainAppSession sender, TransferredEventArgs e)
+    {
+      if (e.Data != null)
+      {
+        Console.WriteLine("SUCCESS! Got twain data on thread {0}.", Environment.CurrentManagedThreadId);
+      }
+      else
+      {
+        Console.WriteLine("BUMMER! No twain data on thread {0}.", Environment.CurrentManagedThreadId);
+      }
+      e.Dispose();
+    }
+
+    private static void Session_StateChanged(TwainAppSession sender, STATE e)
+    {
+      Console.WriteLine($"Session state changed to {sender.State}");
+    }
+
+    private static void Session_SourceDisabled1(TwainAppSession sender, TW_IDENTITY_LEGACY e)
+    {
+      Console.WriteLine($"Session source disabled.");
+      sender.CloseSource();
+    }
+
+    private static void TestThisSource(TwainAppSession session, TW_IDENTITY_LEGACY source)
+    {
+      Console.WriteLine($"Testing data source {source}");
+      Console.WriteLine();
+
+      session.OpenSource(source);
+
+      var rc = session.EnableSource(true, false);
+    }
+  }
+}