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I noticed this while profiling some animations. This improves performance by avoiding the construction and invocation of an Iterator for the List underlying the ObserverList.
List.of does have a special case that recognizes when the argument is another List. But in this case, the ObserverList itself is not a List, so List.of has to go through the ObserverList's `iterator.

The Dart team now recommends avoiding the List.of constructor (see https://stackoverflow.com/a/61541310)

The Dart team now recommends avoiding the List.of constructor (see https://stackoverflow.com/a/61541310)

I wonder if the recommendations given there could be encoded in lints to remind developers to do the right thing. Filed dart-lang/sdk#58716 for that.