Retired::append, to take over a closing owner's images

src/primitives/retired.rs

@@ -5,7 +5,7 @@ use std::sync::Arc;
 use gpui::{RenderImage, Window};
 
 /// Images to free; GPUI keeps each painted image until told.
-#[derive(Default)]
+#[derive(Default, Clone)]
 pub struct Retired(Vec<Arc<RenderImage>>);
 
 impl Retired {
@@ -14,6 +14,11 @@ impl Retired {
         self.0.push(image);
     }
 
+    /// Takes over another owner's waiting images.
+    pub fn append(&mut self, mut other: Retired) {
+        self.0.append(&mut other.0);
+    }
+
     /// Frees images no one else holds; call while painting.
     pub fn release(&mut self, window: &mut Window) {
         // A shared image may still be drawn; it waits.