1 files changed, 17 insertions, 0 deletions
diff --git a/src/SMAPI/Framework/StateTracking/ICollectionWatcher.cs b/src/SMAPI/Framework/StateTracking/ICollectionWatcher.cs
new file mode 100644
index 00000000..7a7759e3
--- /dev/null
+++ b/src/SMAPI/Framework/StateTracking/ICollectionWatcher.cs
@@ -0,0 +1,17 @@
+using System.Collections.Generic;
+
+namespace StardewModdingAPI.Framework.StateTracking
+{
+    /// <summary>A watcher which tracks changes to a collection.</summary>
+    internal interface ICollectionWatcher<out TValue> : IWatcher
+    {
+        /*********
+        ** Accessors
+        *********/
+        /// <summary>The values added since the last reset.</summary>
+        IEnumerable<TValue> Added { get; }
+
+        /// <summary>The values removed since the last reset.</summary>
+        IEnumerable<TValue> Removed { get; }
+    }
+}