Add reactive notifications client

Octokit.Reactive/IObservableNotificationsClient.cs

@@ -0,0 +1,24 @@
+using System;
+using System.Diagnostics.CodeAnalysis;
+
+namespace Octokit.Reactive
+{
+    public interface IObservableNotificationsClient
+    {
+        /// <summary>
+        /// Retrieves all of the <see cref="Notification"/>s for the current user.
+        /// </summary>
+        /// <exception cref="AuthorizationException">Thrown if the client is not authenticated.</exception>
+        /// <returns>A <see cref="IObservable{Notification}"/> of <see cref="Notification"/>.</returns>
+        [SuppressMessage("Microsoft.Design", "CA1024:UsePropertiesWhereAppropriate")]
+        IObservable<Notification> GetAllForCurrent();
+
+        /// <summary>
+        /// Retrieves all of the <see cref="Notification"/>s for the current user specific to the specified repository.
+        /// </summary>
+        /// <exception cref="AuthorizationException">Thrown if the client is not authenticated.</exception>
+        /// <returns>A <see cref="IObservable{Notification}"/> of <see cref="Notification"/>.</returns>
+        IObservable<Notification> GetAllForRepository(string owner, string name);
+
+    }
+}