Add a dummy bench case

bench/index.ts

@@ -0,0 +1,14 @@
+import { Bench } from "tinybench";
+
+const bench = new Bench({ name: "MapArray get", time: 300 });
+
+bench
+	.add("foo", () => {
+		console.log("foo");
+	})
+	.add("bar", () => {
+		console.log("bar");
+	});
+
+await bench.run();
+console.table(bench.table());