Sealing sinks for Sum operators.

Rx.NET/Source/src/System.Reactive/Linq/Observable/Sum.cs

@@ -20,7 +20,7 @@ namespace System.Reactive.Linq.ObservableImpl
             return _source.SubscribeSafe(sink);
         }
 
-        class _ : Sink<double>, IObserver<double>
+        private sealed class _ : Sink<double>, IObserver<double>
         {
             private double _sum;
 
@@ -66,7 +66,7 @@ namespace System.Reactive.Linq.ObservableImpl
             return _source.SubscribeSafe(sink);
         }
 
-        class _ : Sink<float>, IObserver<float>
+        private sealed class _ : Sink<float>, IObserver<float>
         {
             private double _sum; // This is what LINQ to Objects does!
 
@@ -112,7 +112,7 @@ namespace System.Reactive.Linq.ObservableImpl
             return _source.SubscribeSafe(sink);
         }
 
-        class _ : Sink<decimal>, IObserver<decimal>
+        private sealed class _ : Sink<decimal>, IObserver<decimal>
         {
             private decimal _sum;
 
@@ -158,7 +158,7 @@ namespace System.Reactive.Linq.ObservableImpl
             return _source.SubscribeSafe(sink);
         }
 
-        class _ : Sink<int>, IObserver<int>
+        private sealed class _ : Sink<int>, IObserver<int>
         {
             private int _sum;
 
@@ -215,7 +215,7 @@ namespace System.Reactive.Linq.ObservableImpl
             return _source.SubscribeSafe(sink);
         }
 
-        class _ : Sink<long>, IObserver<long>
+        private sealed class _ : Sink<long>, IObserver<long>
         {
             private long _sum;
 
@@ -272,7 +272,7 @@ namespace System.Reactive.Linq.ObservableImpl
             return _source.SubscribeSafe(sink);
         }
 
-        class _ : Sink<double?>, IObserver<double?>
+        private sealed class _ : Sink<double?>, IObserver<double?>
         {
             private double _sum;
 
@@ -319,7 +319,7 @@ namespace System.Reactive.Linq.ObservableImpl
             return _source.SubscribeSafe(sink);
         }
 
-        class _ : Sink<float?>, IObserver<float?>
+        private sealed class _ : Sink<float?>, IObserver<float?>
         {
             private double _sum; // This is what LINQ to Objects does!
 
@@ -366,7 +366,7 @@ namespace System.Reactive.Linq.ObservableImpl
             return _source.SubscribeSafe(sink);
         }
 
-        class _ : Sink<decimal?>, IObserver<decimal?>
+        private sealed class _ : Sink<decimal?>, IObserver<decimal?>
         {
             private decimal _sum;
 
@@ -413,7 +413,7 @@ namespace System.Reactive.Linq.ObservableImpl
             return _source.SubscribeSafe(sink);
         }
 
-        class _ : Sink<int?>, IObserver<int?>
+        private sealed class _ : Sink<int?>, IObserver<int?>
         {
             private int _sum;
 
@@ -471,7 +471,7 @@ namespace System.Reactive.Linq.ObservableImpl
             return _source.SubscribeSafe(sink);
         }
 
-        class _ : Sink<long?>, IObserver<long?>
+        private sealed class _ : Sink<long?>, IObserver<long?>
         {
             private long _sum;