TiledImageSource

Externally owned immutable description of one logical raster assembled from revisioned tiles.

Source identity defines one complete generation: bounds, levels, tile grid geometry, and the meaning of every tile revision remain unchanged while the same instance is used. Applications replace the source instance to publish another generation. A retained component calls tile on its owner thread only for its bounded visible and overscan working set, independently subscribes to each returned source, and closes those observations without closing this source. Tile callbacks may run on any thread under the ordinary StateSource contract and must never expose mutable image storage. Every edge-tile envelope implied by bounds and levels must remain representable in the Long coordinate space.