Reading some Rust code examples in documentation and blogs, I can see the use of Box<T> declaration. Like:
struct Schema {
commands: Vec<Box<dyn Migration>>,
}According to the official Rust documentation: "All values in Rust are stack allocated by default. Values can be boxed (allocated on the heap) by creating a Box<T>. A box is a smart pointer to a heap allocated value of type T. When a box goes out of scope, its destructor is called, the inner object is destroyed, and the memory on the heap is freed."