wip: lots of changes to diffing

examples/manually.rs

@@ -0,0 +1,23 @@
+use dioxus_core::*;
+
+fn main() {
+    use DomEdit::*;
+
+    // .. should result in an "invalid node tree"
+    let edits = vec![
+        CreateElement { tag: "div", id: 0 },
+        // CreatePlaceholder { id: 1 },
+        CreateElement { tag: "h1", id: 2 },
+        CreateTextNode {
+            text: "hello world",
+            id: 3,
+        },
+        AppendChildren { many: 1 },
+        AppendChildren { many: 1 },
+        AppendChildren { many: 1 },
+        // ReplaceWith { many: 1 },
+    ];
+    dioxus_webview::WebviewRenderer::run_with_edits(App, (), |c| c, Some(edits)).expect("failed");
+}
+
+const App: FC<()> = |cx| todo!();