Simulation prune tally (#299)

* Add pruning methods

* Call pruning on node step method

* Fix tally retain closure

simulations/src/node/carnot/event_builder.rs

@@ -36,6 +36,15 @@ impl EventBuilder {
         }
     }
 
+    /// At some point we need to clear old votes or RAM just goes brrrrrr
+    pub fn prune_by_view(&mut self, view: View) {
+        self.vote_message.prune(view);
+        self.leader_vote_message.prune(view);
+        self.timeout_message.prune(view);
+        self.leader_new_view_message.prune(view);
+        self.new_view_message.prune(view);
+    }
+
     fn local_timeout(&mut self, view: View, elapsed: Duration) -> bool {
         if self.timeout_handler.step(view, elapsed) {
             self.timeout_handler.prune_by_view(view);

simulations/src/node/carnot/mod.rs

@@ -533,6 +533,8 @@ impl<
                     || matches!(m, CarnotMessage::Proposal(_) | CarnotMessage::TimeoutQc(_))
             });
         self.message_cache.prune(self.engine.current_view().prev());
+        self.event_builder
+            .prune_by_view(self.engine.current_view().prev());
         self.message_cache.update(other_view_messages);
         current_view_messages.append(&mut self.message_cache.retrieve(self.engine.current_view()));
 

simulations/src/node/carnot/tally.rs

@@ -22,4 +22,8 @@ impl<T: core::hash::Hash + Eq + Clone> Tally<T> {
             None
         }
     }
+
+    pub fn prune(&mut self, view: View) {
+        self.cache.retain(|v, _| v > &view);
+    }
 }