Add markers to event stream

src/emulator/shrooms_vb_core.rs

@@ -1,4 +1,4 @@
-use std::{ffi::c_void, ptr, slice};
+use std::{borrow::Cow, ffi::c_void, ptr, slice};
 
 use anyhow::{Result, anyhow};
 use bitflags::bitflags;
@@ -191,6 +191,9 @@ extern "C" fn on_frame(sim: *mut VB) -> c_int {
     // There is no way for the userdata to be null or otherwise invalid.
     let data: &mut VBState = unsafe { &mut *vb_get_user_data(sim).cast() };
     data.frame_seen = true;
+    if data.monitor.enabled {
+        data.monitor.event = Some(SimEvent::Marker(Cow::Borrowed("Frame Drawn")));
+    }
     1
 }
 
@@ -328,6 +331,7 @@ pub enum SimEvent {
     Halt,
     Interrupt(u16, u32),
     Reti,
+    Marker(Cow<'static, str>),
 }
 
 struct EventMonitor {