diff --git a/src/api/controller.rs b/src/api/controller.rs
index 0a8b990..3170256 100644
--- a/src/api/controller.rs
+++ b/src/api/controller.rs
@@ -45,8 +45,12 @@ pub trait Controller<T : Sized + Send + Sync> : Sized + Send + Sync {
 		}
 	}
 
-	fn callback(&self, cb: ControllerCallback<Self>);
+	/// registers a callback to be called on receive.
+	///
+	/// there can only be one callback at any given time.
+	fn callback(&self, cb: impl Into<ControllerCallback<Self>>);
 
+	/// clears the currently registered callback.
 	fn clear_callback(&self);
 
 	/// block until next value is available without consuming it
diff --git a/src/buffer/controller.rs b/src/buffer/controller.rs
index 2766056..acbf201 100644
--- a/src/buffer/controller.rs
+++ b/src/buffer/controller.rs
@@ -98,8 +98,8 @@ impl Controller<TextChange> for BufferController {
 		Ok(())
 	}
 
-	fn callback(&self, cb: ControllerCallback<BufferController>) {
-		if self.0.callback.send(Some(cb)).is_err() {
+	fn callback(&self, cb: impl Into<ControllerCallback<BufferController>>) {
+		if self.0.callback.send(Some(cb.into())).is_err() {
 			// TODO should we panic? we failed what we were supposed to do
 			tracing::error!("no active buffer worker to run registered callback!");
 		}
diff --git a/src/cursor/controller.rs b/src/cursor/controller.rs
index fe862e4..281d412 100644
--- a/src/cursor/controller.rs
+++ b/src/cursor/controller.rs
@@ -63,8 +63,8 @@ impl Controller<Cursor> for CursorController {
 		Ok(self.0.last_op.lock().await.changed().await?)
 	}
 
-	fn callback(&self, cb: ControllerCallback<CursorController>) {
-		if self.0.callback.send(Some(cb)).is_err() {
+	fn callback(&self, cb: impl Into<ControllerCallback<CursorController>>) {
+		if self.0.callback.send(Some(cb.into())).is_err() {
 			// TODO should we panic? we failed what we were supposed to do
 			tracing::error!("no active cursor worker to run registered callback!");
 		}
diff --git a/src/ffi/lua.rs b/src/ffi/lua.rs
index 026b625..723c340 100644
--- a/src/ffi/lua.rs
+++ b/src/ffi/lua.rs
@@ -207,12 +207,12 @@ impl LuaUserData for CodempBufferController {
 
 		methods.add_method("clear_callback", |_, this, ()| Ok(this.clear_callback()));
 		methods.add_method("callback", |_, this, (cb,):(LuaFunction,)| {
-			this.callback(ControllerCallback::from(move |controller: CodempBufferController| {
+			this.callback(move |controller: CodempBufferController| {
 				let _c = controller.clone();
 				if let Err(e) = cb.call::<(CodempBufferController,), ()>((controller,)) {
 					tracing::error!("error running buffer#{} callback: {e}", _c.name());
 				}
-			}));
+			});
 			Ok(())
 		});
 	}