pub trait Layer {
fn name(&self) -> Option<&'static str>;
fn event(
&mut self,
ctx: &mut EventCtx<'_>,
app: &mut App
) -> Option<LayerOutcome>;
fn draw(&self, g: &mut GfxCtx<'_>, app: &App);
fn draw_minimap(&self, g: &mut GfxCtx<'_>);
}