One answer of a source: its rows, as a table, and what it actually served (spec/01 §3).

A delivery is a handful of terms beside its table, never per row:

• table: the rows, a Macaw.Data.Table. new/2 reads any source shape into one at the edge, so a gap stays nil: absence is never zero.
• schema: the version of the schema the rows were produced under (Macaw.Data.Schema.version/1), never the schema itself, which Macaw.Data.Schema.Cache holds by version; nil when the source has none.
• served: what this answer served, which may differ from what was asked:
  • window: a range [from, to], a box over a :point window field %{west: w, south: s, east: e, north: n}, or nil;
  • resolution: the spacing of the rows as served (seconds, or a name such as :minute), or nil;
  • capped: whether the source stopped short of the window it was asked for;
  • reduced_by: who brought the rows within budget, :source or :runtime, or nil when nobody had to;
  • params: the parameters it was answered for, a map;
  • note: a line for a person ("coarsened from raw"), or nil.

• origin: where it came from, %{source: name, request: digest, as_of: time | nil}, or nil.

The shape of visualize's Visualize.Data.Delivery, whose facts are flat and whose reduced_by is :feed or :visualize, is spec/01 §3's here.

Examples

iex> alias Macaw.Data.{Delivery, Table}
iex> d = Delivery.new(%{t: [1, 2], v: [3, nil]}, served: [window: [0, 10]], schema: "ab12")
iex> Table.rows(d.table)
[%{t: 1, v: 3}, %{t: 2, v: nil}]
iex> {d.served.window, d.served.capped, d.served.reduced_by}
{[0, 10], false, nil}