Implement observable oauth client

Rx will never die

Octokit.Reactive/Clients/ObservableOauthClient.cs

@@ -0,0 +1,28 @@
+using System;
+using System.Reactive.Linq;
+using System.Reactive.Threading.Tasks;
+
+namespace Octokit.Reactive
+{
+    public class ObservableOauthClient : IObservableOauthClient
+    {
+        readonly IGitHubClient _client;
+
+        public ObservableOauthClient(IGitHubClient client)
+        {
+            Ensure.ArgumentNotNull(client, "client");
+
+            _client = client;
+        }
+
+        public IObservable<Uri> GetGitHubLoginUrl(OauthLoginRequest request)
+        {
+            return Observable.Return(_client.Oauth.GetGitHubLoginUrl(request));
+        }
+
+        public IObservable<OauthToken> CreateAccessToken(OauthTokenRequest request)
+        {
+            return _client.Oauth.CreateAccessToken(request).ToObservable();
+        }
+    }
+}