What's the status/blocker for `allocator_api` to be stabilized?

I've been finding myself drawn to other languages like Zig lately. Don't get me wrong, I love Rust, most of the reason for this is because of how much simpler & builtin the ability to swap out allocators is.

Considering Rust promotes itself as being a language focused on performance it seems to me that the ability to customize allocation strategies is quite essential. Ideally the standard library should even come with basic allocators like an arena, stack, etc.

I acknowledge that Rust is a powerful language and you can implement this stuff in user space as the excellent bumpalo crate demonstrates, nevertheless it's still cumbersome as if it's missing data structures (like HashMap) you have to implement it on your own somehow. Or if you want your own allocator you need to copy over all the data structures you want to use. This is a non-trivial task!

What's the status of stabilizing this stdlib feature? I personally really want it as it would help me and I believe others, write better code, more easily.