dont use flushSync

packages/svelte/src/internal/client/reactivity/forks.js

@@ -114,7 +114,7 @@ export class Fork {
 	 */
 	run(fn) {
 		active_fork = this;
-		flushSync(fn);
+		fn();
 	}
 
 	increment() {

packages/svelte/tests/runtime-runes/samples/async-attribute/_config.js

@@ -27,6 +27,7 @@ export default test({
 		assert.htmlEqual(p.outerHTML, '<p class="cool">hello</p>');
 
 		flushSync(() => neat.click());
+		await Promise.resolve();
 		await tick();
 		assert.htmlEqual(p.outerHTML, '<p class="neat">hello</p>');
 	}

packages/svelte/tests/runtime-runes/samples/async-derived/_config.js

@@ -28,6 +28,7 @@ export default test({
 
 		flushSync(() => increment.click());
 		await Promise.resolve();
+		await Promise.resolve();
 		await tick();
 		assert.htmlEqual(p.innerHTML, '2a');
 
@@ -36,6 +37,7 @@ export default test({
 
 		flushSync(() => resolve_b.click());
 		await Promise.resolve();
+		await Promise.resolve();
 		await tick();
 		assert.htmlEqual(p.innerHTML, '2b');