When true, Retree prepares this node's tree when the node is proxied.
This pays the lazy child-proxy cost up front instead of on first nested access.
Optional
Maximum nested object depth to prepare.
Defaults to Infinity, which prepares every reachable non-ignored object/array/Map/Set value below this node.
Infinity
When true, Retree prepares this node's tree when the node is proxied.