Finalize GC memory

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With the knowledge that 'delete' will be deprecated soon:
Is there then still a way to finalize GC memory? I know it's 
unsafe etc. but is there a way? I know of 'destroy' but it does 
not finalize anything and AFAIK it's not safe and has also side 
effects. And it does not call the DTor if any struct is allocated 
with 'new'.
I tried GC.free, GC.collect, destroy and a few other things, but 
except of 'delete' nothing finalize the memory.
Thoughts?