onImage property Null safety
final
Callback for getting notified that an image is available.
This callback may fire multiple times (e.g. if the ImageStreamCompleter that drives the notifications fires multiple times). An example of such a case would be an image with multiple frames within it (such as an animated GIF).
For more information on how to interpret the parameters to the callback, see the documentation on ImageListener.
See also:
Implementation
final ImageListener onImage;