todo

property binding optimization
- would no longer allow cleanup() usage in binding scopes
solution to nested reactivity, see: SolidJS stores
optimize wide graph updating
implement from solid:
- Portal
- batch
optimize indexes() double-diffing
improve crash course, some sections feel like information dumps
reactive scopes
- define behavior of creating a reactive scope within a non-root reactive scope
  - i.e. an effect within an effect
  - error on attempt for now
- define behavior of destruction of a node with a child, where the node and its child are in separate, non-nested root reactive scopes.
  - should destruction of the parent also destroy the child?
  - or should destruction of the parent silently disconnect the child, without invoking the child's cleanups?
```
graph LR

subgraph root1
    parent
end

subgraph root2
    child
end

parent --> child
```