Fixing an issue with thread creation and selected items notifications.

Wino.Core.Domain/Models/MailItem/IMailHashContainer.cs

@@ -0,0 +1,15 @@
+using System;
+using System.Collections.Generic;
+
+namespace Wino.Core.Domain.Models.MailItem
+{
+    /// <summary>
+    /// An interface that returns the UniqueId store for IMailItem.
+    /// For threads, it may be multiple items.
+    /// For single mails, it'll always be one item.
+    /// </summary>
+    public interface IMailHashContainer
+    {
+        IEnumerable<Guid> GetContainingIds();
+    }
+}