fix: fix the issue that useSWR revalidation isn't triggered if the

useSWR call happens after mutation. E.g.:

   req------------->res
mutate------->end

In this case, the res would be ignored while req would not be triggered
a revalidation.

_internal/src/utils/mutate.ts

@@ -97,8 +97,8 @@ export async function internalMutate<Data>(
       cache
     ) as GlobalState
 
-    const revalidators = EVENT_REVALIDATORS[key]
     const startRevalidate = () => {
+      const revalidators = EVENT_REVALIDATORS[key]
       if (revalidate) {
         // Invalidate the key by deleting the concurrent request markers so new
         // requests will not be deduped.