diff --git a/src/main.rs b/src/main.rs
index dee4439..c194805 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -10,6 +10,7 @@ use tempfile::NamedTempFile;
 
 mod api;
 mod mpv_setup;
+mod util;
 
 #[derive(Parser)]
 struct Args {
diff --git a/src/util.rs b/src/util.rs
new file mode 100644
index 0000000..2e2f895
--- /dev/null
+++ b/src/util.rs
@@ -0,0 +1 @@
+mod id_pool;
diff --git a/src/util/id_pool.rs b/src/util/id_pool.rs
new file mode 100644
index 0000000..d699559
--- /dev/null
+++ b/src/util/id_pool.rs
@@ -0,0 +1,13 @@
+pub struct IdPool {}
+
+impl IdPool {
+    pub fn new() -> Self {
+        Self {}
+    }
+
+    pub fn request_id(&self) -> u64 {
+        0
+    }
+
+    pub fn release_id(&self, id: u64) {}
+}