fetch() range requests against one static
full-data ~43MB file (nyc311-cube-v15.dcb2) — no database, no query engine, no dependencies.
leaderboards come from a 4,794-row all-time section held in memory; each line is one contiguous slice of a
per-dimension daily section; brushes read a time-sorted weekly section and snap to whole weeks.
this demo applies one leaderboard filter at a time (the cube carries all 2⁴ dimension subsets).
formats, readers and pipeline: http-range-drilldown-cubes.