add unconstrained feature to service worker

Signed-off-by: Jason Volk <jason@zemos.net>

src/service/service.rs

@@ -39,6 +39,11 @@ pub(crate) trait Service: Any + Send + Sync {
 	/// Return the name of the service.
 	/// i.e. `crate::service::make_name(std::module_path!())`
 	fn name(&self) -> &str;
+
+	/// Return true if the service worker opts out of the tokio cooperative
+	/// budgeting. This can reduce tail latency at the risk of event loop
+	/// starvation.
+	fn unconstrained(&self) -> bool { false }
 }
 
 /// Args are passed to `Service::build` when a service is constructed. This