Issue #23: implement sta runtime and message pump

src/MxGateway.Worker/Sta/StaComApartmentInitializer.cs

@@ -0,0 +1,31 @@
+using System;
+using System.Runtime.InteropServices;
+
+namespace MxGateway.Worker.Sta;
+
+public sealed class StaComApartmentInitializer : IStaComApartmentInitializer
+{
+    private const uint CoInitializeApartmentThreaded = 0x2;
+    private const int SOk = 0;
+    private const int SFalse = 1;
+
+    public void Initialize()
+    {
+        int hresult = CoInitializeEx(IntPtr.Zero, CoInitializeApartmentThreaded);
+        if (hresult != SOk && hresult != SFalse)
+        {
+            throw new COMException("Failed to initialize the worker STA COM apartment.", hresult);
+        }
+    }
+
+    public void Uninitialize()
+    {
+        CoUninitialize();
+    }
+
+    [DllImport("ole32.dll")]
+    private static extern int CoInitializeEx(IntPtr reserved, uint coInit);
+
+    [DllImport("ole32.dll")]
+    private static extern void CoUninitialize();
+}