Make memory watching work before sim is started

src/graphics.rs

@@ -142,7 +142,6 @@ impl BufferPool {
     }
 }
 
-#[derive(Debug)]
 struct Buffer {
     data: Mutex<Vec<u8>>,
     id: AtomicU64,
@@ -155,3 +154,10 @@ impl Buffer {
         }
     }
 }
+impl std::fmt::Debug for Buffer {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        f.debug_struct("Buffer")
+            .field("id", &self.id)
+            .finish_non_exhaustive()
+    }
+}