Implement placement new concept

[elfenpiff]

Implement placement new concept

[elBoberido]

There is already a workaround for this available by using

let mut sample = publisher.loan_uninit()?;
let sample = unsafe {
    sample
        .payload_mut()
        .as_mut_ptr()
        .write(LargdDataType::default());

    sample.assume_init()
};

It should work reliably with release builds but might fail with debug builds.

We need a long term solution but I think a build-in Rust solution would be ideal. Maybe this is something we could engage in the Rust community and try to speed it up?

[elfenpiff]

@elBoberido, we could try, but I doubt we can realize this in the following months.

I can't entirely agree with calling this reliable when this algorithm depends on a release optimization. For whatever reason, this could be turned off in some corner cases, or the compiler may not be able to realize that it can perform this optimization.

And what if the user, who is using iceoryx, integrates this into unit tests - then it will cause problems again. With this we would also enforce our users to always build in release mode, also during development, which would cause additional problems.

So my take on this is that we require a quick and comfortable solution and we can use our solution as a discussion basis for the Rust community to come to a build-in Rust solution. What do you think?

[elBoberido]

@elfenpiff I think there are more pressing issues but it's up to you.