The `sizes` property doesn't appear to have been used ever since the code was first split into main/worker-threads, which is so many years ago that I wasn't able to easily find exactly in which PR/commit it became unused.
The `encoding` property is always assigned the `properties.baseEncoding` value, however the `PartialEvaluator` doesn't actually compute/set that value any more. Again it was difficult to determine when it became unused, but it's been that way for years.
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