pub fn settle_tree(world: &mut World)Expand description
Bring a just-spawned tree in line with the state the app starts in, before its first tick.
on_start has run by the time the tree spawns and its signal writes are in
the store, but the <if> and <for> bodies they open are mounted by the
reconcilers, which run on a tick. Run here once, so the tree the first
tick indexes already holds them: on_ready, which runs on that tick, finds
an element inside an <if> that starts truthy, and a node it appends
there attaches. Writes queued on the external buses (a host’s typed
signal builtins, an embedder writing before the run) are taken in first.
One pass: an <if> inside a body mounted here mounts on the first tick.