fix empty handler class

Author: David Kline (ANALOG)

Assets/MixedRealityToolkit-SDK/Features/SpatialAwareness/System/Handlers/MixedRealitySpatialAwarenessSurfaceFindingHandler.cs

@@ -1,5 +1,32 @@
-
+// Copyright (c) Microsoft Corporation. All rights reserved.
+// Licensed under the MIT License. See LICENSE in the project root for license information.
 
-public class MixedRealitySpatialAwarenessSurfaceFindingHandler
+using Microsoft.MixedReality.Toolkit.Core.EventDatum.SpatialAwarenessSystem;
+using Microsoft.MixedReality.Toolkit.Core.Interfaces.SpatialAwarenessSystem.Handlers;
+
+namespace Microsoft.MixedReality.Toolkit.SDK.SpatialAwarenessSystem.Handlers
 {
+    /// <summary>
+    /// Class providing the default implementation of the <see cref="IMixedRealitySpatialAwarenessSurfaceFindingHandler"/> interface.
+    /// </summary>
+    public class MixedRealitySpatialAwarenessSurfaceFindingHandler : IMixedRealitySpatialAwarenessSurfaceFindingHandler
+    {
+        /// <inheritdoc />
+        public void OnSurfaceAdded(MixedRealitySpatialAwarenessSurfaceFindingEventData eventData)
+        {
+            // todo
+        }
+
+        /// <inheritdoc />
+        public void OnSurfaceUpdated(MixedRealitySpatialAwarenessSurfaceFindingEventData eventData)
+        {
+            // todo
+        }
+
+        /// <inheritdoc />
+        public void OnSurfaceRemoved(MixedRealitySpatialAwarenessSurfaceFindingEventData eventData)
+        {
+            // todo
+        }
+    }
 }