diff --git a/core/src/com/riiablo/asset/AsyncTask.java b/core/src/com/riiablo/asset/AsyncTask.java
new file mode 100644
index 00000000..1f5b335c
--- /dev/null
+++ b/core/src/com/riiablo/asset/AsyncTask.java
@@ -0,0 +1,21 @@
+package com.riiablo.asset;
+
+class AsyncTask implements Runnable {
+  final AssetDesc asset;
+  final Callback callback;
+
+  AsyncTask(AssetDesc asset, Callback callback) {
+    this.asset = asset;
+    this.callback = callback;
+  }
+
+  @Override
+  public void run() {
+    //...
+    callback.onAsyncTaskFinished(this, asset);
+  }
+
+  public interface Callback {
+    void onAsyncTaskFinished(AsyncTask task, AssetDesc asset);
+  }
+}
diff --git a/core/src/com/riiablo/asset/SyncTask.java b/core/src/com/riiablo/asset/SyncTask.java
new file mode 100644
index 00000000..a039631d
--- /dev/null
+++ b/core/src/com/riiablo/asset/SyncTask.java
@@ -0,0 +1,21 @@
+package com.riiablo.asset;
+
+class SyncTask implements Runnable {
+  final AssetDesc asset;
+  final Callback callback;
+
+  SyncTask(AssetDesc asset, Callback callback) {
+    this.asset = asset;
+    this.callback = callback;
+  }
+
+  @Override
+  public void run() {
+    //...
+    callback.onSyncTaskFinished(this, asset);
+  }
+
+  public interface Callback {
+    void onSyncTaskFinished(SyncTask task, AssetDesc asset);
+  }
+}