The default implementation checks both pending and cached
image buckets.

bool

containsKey

Object

key

return

_pendingImages

key

!=

null

||

_cache

key

!=

null

ImageProvider changes

To solve this issue, resolve is now marked as non-virtual,
and two new protected methods have been added: createStream()
and resolveStreamForKey().
These methods allow subclasses to control most of the behavior
of resolve, without having to duplicate all the error handling work.
It also allows subclasses that compose ImageProviders
to be more confident that there is only one public entrypoint
to the various chained providers.

Migration guide

ImageCache change

Before migration, the code would not have an override of containsKey.