Specifically disable Immer strict iteration for perf

Author: markerikson

packages/toolkit/src/index.ts

@@ -11,6 +11,7 @@ export {
   isDraft,
 } from 'immer'
 export type { Draft, WritableDraft } from 'immer'
+import { setUseStrictIteration } from 'immer'
 export {
   createSelector,
   createSelectorCreator,
@@ -216,3 +217,10 @@ export type {
 } from './tsHelpers'
 
 export { formatProdErrorMessage } from './formatProdErrorMessage'
+
+// Immer 10.2 defaults to still using strict iteration (specifically
+// `Reflect.ownKeys()` for symbols support). However, we assume that
+// Redux users are not using symbols as state keys, so we'll override
+// this to prefer `Object.keys()` instead, as it provides a ~10% speedup.
+// If users do need symbol support, they can call `setUseStrictIteration(true)` themselves.
+setUseStrictIteration(false)