Applying Placement New to druntime and phobos

[Per Nordlöw]

On Monday, 3 March 2025 at 15:12:20 UTC, Paul Backus wrote:
> I think a good first step would be to try replacing the current 
> implementation(s) of `emplace` with calls to placement new.

Do you mean doing this before replacing the top-level calls top 
`emplace`?