So long as I am able to prove that any instantiation of Foo.bar is done with a Sendable type (like with my suggested initializer) then it is safe, no? I guess the main risk is if that requirement becomes unintentionally relaxed by another developer in the future?
If the use of a Sendable version of AnyHashable is required, are there any alternatives (outside of rolling my own AnyHashableSendable type) you'd suggest?