Is polymorphism with sized traits possible in rust

I am using a library that exposes a trait which requires it to be Sized.

I am using an object that implements this trait, and am trying to create an array that include all those instances. With a non-sized trait I would use something like Vec<Box<dyn MyNonSizedTrait>>, but with the Sized trait it's impossible, the compiler complains with the trait MySizedTrait cannot be made into an object.

Is there any way to work around that?

Here is an example of what I'm trying to do:

trait A: Sized {
    fn do_something(&self);  
}
    
struct B;

impl A for B {
    fn do_something(&self){
        println!("This is B")
    }
}
    
struct C;
    
impl A for C {
    fn do_something(&self) {
        println!("This is C")
    }
}
    
    
fn my_do_something(d: &[Box<dyn A>]) {
    for i in d {
        i.do_something(); 
    }
}
    
fn main() {
    let mut d: Vec<Box<dyn A>> = Vec::new();
    d.push(Box::new(B));  
    d.push(Box::new(C)); 
    my_do_something(&d); 
}