re-worked message sending

src/Core/Abstractions/IBroadcasterService.cs

@@ -1,11 +1,12 @@
-using System;
+using Bit.Core.Models.Domain;
+using System;
 
 namespace Bit.Core.Abstractions
 {
     public interface IBroadcasterService
     {
-        void Send<T>(T message, string id = null);
-        void Subscribe<T>(string id, Action<T> messageCallback);
+        void Send(Message message, string id = null);
+        void Subscribe(string id, Action<Message> messageCallback);
         void Unsubscribe(string id);
     }
 }

src/Core/Abstractions/IMessagingService.cs

@@ -2,6 +2,6 @@
 {
     public interface IMessagingService
     {
-        void Send<T>(string subscriber, T arg = default(T));
+        void Send(string subscriber, object arg = null);
     }
 }