Use Ref and OutRef for C++ delegates
#3447
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This fixes the issue of C++ delegates (C++ function pointer/callback types) are generated with parameters that assume ownership is passed into the function. This is fine for sys-style bindings where all types are copyable but not so for regular bindings where some times might require ownership or lifetime management. That's exactly what
RefandOutRefhandle so that's what these delegates now use for their parameters.A somewhat contrived test is provided that implements
PFNGETACTIVATIONFACTORYto verify that such delegates can be both implemented and called in Rust. This highlighted a limitation in the fact thatRefnow has no lifetime parameter (#3433 #3435) and thus makes it unsafe to construct on the call side. This is unfortunate, so I'll rethinkRefand see if we can reintroduce the lifetime for cases where this needs to be called safely.Fixes: #3446