Gets the data for the tile at the given coordinates.
Some data sources may return data multiple times. For example,
[class@TileDownloader] may return data from a cache, then return updated
data from the network. [signal@ShumateDataSource::received-data] is emitted
each time data is received, then @callback is called after the last update.
Gets the data for the tile at the given coordinates.
Some data sources may return data multiple times. For example, [class@TileDownloader] may return data from a cache, then return updated data from the network. [signal@ShumateDataSource::received-data] is emitted each time data is received, then @callback is called after the last update.