Byte-range reader for accessing FGB files.
Tile zoom level.
Tile column.
Tile row.
The sources (or source) the tile is rendered from.
Optionaloptions: TileOptions & IoOptions & Pick<RequestOptions, "signal">
The tiling and I/O options the tile is rendered with,
and an optional abort signal.
A strong, quoted ETag, or null when a source's connector
reports no version tag.
Compute the ETag of a tile without rendering it (see TileServer.tileETag), using the same cache as tile.