stubbed the observable clients

Octokit.Reactive/Clients/IObservableUserKeysClient.cs

@@ -0,0 +1,31 @@
+using System;
+
+namespace Octokit.Reactive
+{
+    /// <summary>
+    /// A client for GitHub's User Keys API.
+    /// </summary>
+    /// <remarks>
+    /// See the <a href="http://developer.github.com/v3/users/keys/">User Keys API documentation</a> for more information.
+    /// </remarks>
+    public interface IObservableUserKeysClient
+    {
+        /// <summary>
+        /// Gets all public keys for the authenticated user.
+        /// </summary>
+        /// <remarks>
+        /// https://developer.github.com/v3/users/keys/#list-your-public-keys
+        /// </remarks>
+        /// <returns>The <see cref="PublicKey"/>s for the authenticated user.</returns>
+        IObservable<PublicKey> GetAll();
+
+        /// <summary>
+        /// Gets all verified public keys for a user.
+        /// </summary>
+        /// <remarks>
+        /// https://developer.github.com/v3/users/keys/#list-public-keys-for-a-user
+        /// </remarks>
+        /// <returns>The <see cref="PublicKey"/>s for the user.</returns>
+        IObservable<PublicKey> GetAll(string userName);
+    }
+}