nested record iframe (#63)

* pick nested branch

* iframe snapshot

* temp: add bundle file to git

* revert ignore file

* refactor iframe impl
1. do callback one iframe is loaded, let rrweb handle the rest
2. handle iframe as normal element in rebuild

* rename hook function

src/types.ts

@@ -47,13 +47,16 @@ export type commentNode = {
   textContent: string;
 };
 
-export type serializedNode =
+export type serializedNode = (
   | documentNode
   | documentTypeNode
   | elementNode
   | textNode
   | cdataNode
-  | commentNode;
+  | commentNode
+) & {
+  rootId?: number;
+};
 
 export type serializedNodeWithId = serializedNode & { id: number };