diff --git a/Octokit.Reactive/Clients/ObservableEventsClient.cs b/Octokit.Reactive/Clients/ObservableEventsClient.cs
index e317d2de..df5d8fdc 100644
--- a/Octokit.Reactive/Clients/ObservableEventsClient.cs
+++ b/Octokit.Reactive/Clients/ObservableEventsClient.cs
@@ -5,7 +5,7 @@ namespace Octokit.Reactive
 {
     public class ObservableEventsClient : IObservableEventsClient
     {
-        IConnection _connection;
+        readonly IConnection _connection;
 
         public ObservableEventsClient(IGitHubClient client)
         {