plugin feature events

Pilz.Plugins.Advanced/PluginFeatureController.cs

@@ -9,6 +9,18 @@ namespace Pilz.Plugins.Advanced
 {
     public sealed class PluginFeatureController
     {
+        public delegate void PluginFeatureEventHandler(PluginFeatureController controller, PluginFeature feature);
+
+        /// <summary>
+        /// Fires when a new <see cref="PluginFeature"/> has been registred.
+        /// </summary>
+        public static event PluginFeatureEventHandler? OnPluginFeatureReistred;
+
+        /// <summary>
+        /// Fires when a <see cref="PluginFeature"/> has been unregistred.
+        /// </summary>
+        public static event PluginFeatureEventHandler? OnPluginFeatureUnregistred;
+
         /// <summary>
         /// The default public instance that can be used by plugins and the interface providing software.
         /// </summary>
@@ -41,12 +53,16 @@ namespace Pilz.Plugins.Advanced
         public void Register(PluginFeature module)
         {
             if (!features.Contains(module))
+            {
                 features.Add(module);
+                OnPluginFeatureReistred?.Invoke(this, module);
+            }
         }
 
         public void Unregister(PluginFeature module)
         {
             features.Remove(module);
+            OnPluginFeatureUnregistred?.Invoke(this, module);
         }
 
         public class FeatureController