Add foundation

Toolkit.Foundation/IConfigurationWriter.cs

@@ -0,0 +1,12 @@
+namespace Toolkit.Foundation;
+
+public interface IConfigurationWriter<TConfiguration>
+    where TConfiguration :
+    class
+{
+    void Write(Action<TConfiguration> updateDelegate);
+
+    void Write(object value);
+
+    void Write(TConfiguration value);
+}