Putting IBuffer in its own file.

Ix.NET/Source/System.Interactive/System/Linq/IBuffer.cs

@@ -0,0 +1,16 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the Apache 2.0 License.
+// See the LICENSE file in the project root for more information. 
+
+using System.Collections.Generic;
+
+namespace System.Linq
+{
+    /// <summary>
+    /// Represents a buffer exposing a shared view over an underlying enumerable sequence.
+    /// </summary>
+    /// <typeparam name="T">Element type.</typeparam>
+    public interface IBuffer<out T> : IEnumerable<T>, IDisposable
+    {
+    }
+}

Ix.NET/Source/System.Interactive/System/Linq/Operators/Buffer.cs

@@ -69,12 +69,4 @@ namespace System.Linq
                 yield return buffers.Dequeue();
         }
     }
-
-    /// <summary>
-    ///     Represents a buffer exposing a shared view over an underlying enumerable sequence.
-    /// </summary>
-    /// <typeparam name="T">Element type.</typeparam>
-    public interface IBuffer<out T> : IEnumerable<T>, IDisposable
-    {
-    }
 }