Method barrier

aiscript-arena/src/context.rs:480–483

(this: &Context, parent: GcBox)

            // often) to promote the inlining of the write barrier.
            #[cold]
            fn barrier(this: &Context, parent: GcBox) {
                parent.header().set_color(GcColor::Gray);
                this.gray_again.borrow_mut().push(parent);
            }
            barrier(self, parent);
        }
    }