wip(ssr): reduce reactivity overhead during ssr

packages/reactivity/src/ref.ts

@@ -36,6 +36,14 @@ export function ref(raw?: unknown) {
     return raw
   }
   raw = convert(raw)
+
+  if (__SSR__) {
+    return {
+      _isRef: true,
+      value: raw
+    }
+  }
+
   const r = {
     _isRef: true,
     get value() {
@@ -58,7 +66,7 @@ export function ref(raw?: unknown) {
 export function toRefs<T extends object>(
   object: T
 ): { [K in keyof T]: Ref<T[K]> } {
-  if (__DEV__ && !isReactive(object)) {
+  if (__DEV__ && !__SSR__ && !isReactive(object)) {
     console.warn(`toRefs() expects a reactive object but received a plain one.`)
   }
   const ret: any = {}