Add possibility to configure GitHubClient timeout (#963) (#1693)

* Add possibility to configure GitHubClient timeout (#963)

A first attempt to fix the problem describe in #963 by adding a possibility
to extend the default timeout value (100s)
that is too short to be able to post assets in github release.

* Rename to SetRequestTimeout
Make comments consistent

Octokit.Reactive/ObservableGitHubClient.cs

@@ -54,6 +54,20 @@ namespace Octokit.Reactive
             get { return _gitHubClient.Connection; }
         }
 
+        /// <summary>
+        /// Set the GitHub Api request timeout.
+        /// Useful to set a specific timeout for lengthy operations, such as uploading release assets
+        /// </summary>
+        /// <remarks>
+        /// See more information here: https://technet.microsoft.com/library/system.net.http.httpclient.timeout(v=vs.110).aspx
+        /// </remarks>
+        /// <param name="timeout">The Timeout value</param>
+        public void SetRequestTimeout(TimeSpan timeout)
+        {
+            
+            _gitHubClient.SetRequestTimeout(timeout);
+        }
+
         public IObservableAuthorizationsClient Authorization { get; private set; }
         public IObservableActivitiesClient Activity { get; private set; }
         public IObservableIssuesClient Issue { get; private set; }