fix: wait a microtask for await blocks to reduce UI churn

package.json

@@ -6,7 +6,9 @@
   "type": "module",
   "license": "MIT",
   "packageManager": "pnpm@9.2.0",
-
+  "engines": {
+    "pnpm": "^9.0.0"
+  },
   "repository": {
     "type": "git",
     "url": "git+https://github.com/sveltejs/svelte.git"

packages/svelte/src/internal/client/dom/blocks/await.js

@@ -90,6 +90,8 @@ export function await_block(anchor, get_input, pending_fn, then_fn, catch_fn) {
 					try {
 						set_current_effect(parent_effect);
 						set_current_reaction(parent_reaction);
+						if (then_effect) pause_effect(then_effect);
+						if (catch_effect) pause_effect(catch_effect);
 						pending_effect = branch(() => pending_fn(anchor));
 					} finally {
 						set_current_effect(previous_effect);
@@ -105,9 +107,6 @@ export function await_block(anchor, get_input, pending_fn, then_fn, catch_fn) {
 				}
 			}
 
-			if (then_effect) pause_effect(then_effect);
-			if (catch_effect) pause_effect(catch_effect);
-
 			promise.then(
 				(value) => {
 					if (promise !== input) return;