ListDiffsExtensions extension Null safety



recast<E>(ListDiffArguments<E> args) ListDiffs<E>
undelegate<E>(ListDiffArguments<E> args) ListDiffs<E>
This occurs when the diff was delegated - which means that instead of passing the real instance to the isolate, we passed a safe delegate. When the method returns, we need to rehydrate the results by looking the delegates up in a map.