How to avoid explicitly cloning a variable that is moved to a closure?

[LiveDuo]

Turns out this is possible with arena allocators. Opened a new topic here:

How Leptos avoids cloning variables moved into closures?

I asked a question about explicit cloning and closures a few days ago and turns out there's a way around it. As shown in the example bellow, the reactive-graph library of the Leptos framework managed to pass variables without the Copy trait such as String to closures without explicitly cloning them. use reactive_graph::{owner::ArenaItem, signal::ArcRwSignal, traits::Read}; fn callback_mut(mut cb: impl FnMut() + 'static) { cb(); } fn main() { let counter_arena = ArenaItem::<_>::new_with_…