Add service for resolving on-app-ready callback

src/ElectronNET.AspNet/Runtime/Services/AppReadyCallbackResolver.cs

@@ -0,0 +1,37 @@
+using System;
+using System.Threading.Tasks;
+
+namespace ElectronNET.AspNet.Runtime
+{
+    internal class AppReadyCallbackResolver : IAppReadyCallbackResolver
+    {
+        private readonly Func<Task> _callback;
+
+        public AppReadyCallbackResolver()
+        { }
+
+        public AppReadyCallbackResolver(Func<Task> callback)
+        {
+            _callback = callback;
+        }
+
+        public AppReadyCallbackResolver(string[] args, Func<string[], Task> callback)
+        {
+            _callback = () => callback.Invoke(args);
+        }
+
+        public AppReadyCallbackResolver(IServiceProvider serviceProvider, Func<IServiceProvider, Task> callback)
+        {
+            _callback = () => callback.Invoke(serviceProvider);
+        }
+
+        public AppReadyCallbackResolver(IServiceProvider serviceProvider, string[] args, Func<IServiceProvider, string[], Task> callback)
+        {
+            _callback = () => callback.Invoke(serviceProvider, args);
+        }
+
+        public bool HasCallback => _callback != null;
+
+        public Task Invoke() => _callback?.Invoke() ?? Task.CompletedTask;
+    }
+}

src/ElectronNET.AspNet/Runtime/Services/IAppReadyCallbackResolver.cs

@@ -0,0 +1,11 @@
+using System.Threading.Tasks;
+
+namespace ElectronNET.AspNet.Runtime
+{
+    internal interface IAppReadyCallbackResolver
+    {
+        public bool HasCallback { get; }
+
+        public Task Invoke();
+    }
+}