task: rewrite event handling as a step towards event-based subscriptions

src/buffers.rs

@@ -1,4 +1,4 @@
-use crate::events::{Event, EventBus};
+use crate::events::EventBus;
 use crate::geometry::*;
 use crate::lib8::interpolate::Fract8Ops;
 use crate::power::AsMilliwatts;
@@ -236,7 +236,7 @@ impl Surfaces for BufferedSurfacePool {
 
 
 impl Task for BufferedSurfacePool {
-    fn tick(&mut self, event: &Event, bus: &mut EventBus) {
+    fn on_tick(&mut self, _bus: &mut EventBus) {
         if self.pool.read().unwrap().is_dirty() {
             self.pool.write().unwrap().commit();
         }