TypeId based pointer array.

lib.rs:

An stack array store &T or &mut T as ([TypeId], *const/mut ()) Can be used to pass reference to function call when do not have full control of it's argument.

Example:

// a determined function that you can't modify for arbitrary argument.
fn bar(_arg1: (), mut arg2: PointerArray<'_>) {
    // remove &mut Vec<String> from array.
    let arg3 = arg2.remove_mut::<Vec<String>>().unwrap();
    assert_eq!("arg3", arg3.pop().unwrap());
}

let ptr_array = PointerArray::new();

let mut arg3 = vec![String::from("arg3")];

// insert &mut Vec<String> to array. on Ok(_) the array itself would be returned with
// reference successfully inserted.
let ptr_array = ptr_array.insert_mut(&mut arg3).unwrap();

// pass the array as argument to bar.
bar((), ptr_array);