A target rendered block by block off one table. The target may read @notes, the sum of
the terms added under handles. A node the store answers plays from its samples. A hit is
looked up once; a node reading the stream’s own note sum never, as no store holds one.
One reading off a buffer nothing rendered — an external file, say — under the profile the
caller names. Every representation needing the graph behind it refuses here.
build’s change, holding the stream only to apply it, between two blocks, once the store
answered what it brings in: an exact stream pulled only once its edit is done plays it where
it was issued. build runs again whenever the stream changed under it.
The sample each of roots read bare would end at, None where its support, pruning
included, never ends and such a render refuses for it. Typed together, and no sample.
render through store, from the root down: a node the store answers stands as its
samples, and nothing under it is typed, planned or looked up. What the rest computes is
staged beside the store as the render drops it; only persist writes the store. A failing
store fails no render: it stages nothing more, and its stats say why.