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This is neat, but how does this get away with being zero allocation? It appears to use `Func<T,U>` for its predicates, and since `Func<T>` is a reference type this will allocate. The IL definitely generates definitely seems like it's forming a reference type from what I can tell.

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The JIT can optimize this. I know for sure if there's no captures in the lambda it won't allocate. It's likely also smart enough to recognize when a function parameter doesn't have its lifetime extended past the caller's, which is a case where it would also be possible to not allocate.

To add on that, you can define your lambdas as static to make sure you're not capturing anything by mistake.

Something like dates.Where(static x => x.Date > DateTime.Now)

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