clientCallback

The client callback. Custom raster sourtce can be configured for either direct or asynchronous rendering: When `CustomRasterSourceTileStatusChangedCallback` instance is provided, rendering is asynchronous, and the client should use setStyleCustomRasterSourceTileData() API to provide the tile data. When `CustomRasterSourceTileRenderer` instance is provided, rendering is direct, and the client should render to the tile from within the `CustomRasterSourceTileRenderer.renderToTile()` method.