You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: vtable_size_align_drop.rs
    path of file: ./repos/kani/tests/kani/DynTrait
    
    the code of the file until where you have to start completion: // Copyright Kani Contributors
// SPDX-License-Identifier: Apache-2.0 OR MIT

// This test checks the `size` and `align` fields of vtables, for a
// dynamic trait where two implementing structs have different sizes.
// The strategy is to use the new pointer metadata API:
// https://github.com/rust-lang/rust/issues/81513

#![feature(core_intrinsics)]
#![feature(ptr_metadata)]

use std::intrinsics::size_of;
use std::ptr::drop_in_place;

include!("../Helpers/vtable_utils_ignore.rs");
// Different sized data fields on each struct
struct Sheep {
    pub sheep_num: i32,
}
struct Cow {
    pub cow_num: i8,
}

trait Animal {
    // Instance method signature
    fn noise(&self) -> i32;
}

// Implement the `Animal` trait for `Sheep`.
impl Animal for Sheep {
    fn noise(&self) -> i32 {
        self.sheep_num
    }
}

// Implement the `Animal` trait for `Cow`.
impl Animal for Cow {
    fn noise(&self) -> i32 {
        self.cow_num as i32
    }
}

// Returns some struct that implements Animal, but we do
    
fn main() {
    // The vtable is laid out as the right hand side here:
    //
    // +-------+------------------+
    // | size  |      value       |
    // +-------+------------------+
    // | usize | pointer to drop  |
    // | usize | size in bytes    |
    // | usize | align in bytes   |
    // | ?     | function ptrs... |
    // +-------+------------------+
    //
    // This layout taken from miri's handling:
    // https://github.com/rust-lang/rust/blob/ec487bf3cfc9ce386da25169509fae8f2b4d4eec/compiler/rustc_mir/src/interpret/traits.rs#L155

    // Check layout/values for Sheep
    unsafe {
        let animal_sheep = &*random_animal(1);

        // Check that the struct's data is what we expect
        let data_ptr = data!(animal_sheep);

        // Note: i32 ptr cast
        assert!(*(data_ptr as *mut i32) == 7); // From Sheep

        let vtable_ptr = vtable!(animal_sheep);

        // Drop pointer
        assert!(drop_from_vtable(vtable_ptr) == drop_in_place::<Sheep> as *mut ());

        // Size and align as usizes
        assert!(size_from_vtable(vtable_ptr) == size_of::<i32>());
        assert!(align_from_vtable(vtable_ptr) == size_of::<i32>());
    }
    // Check layout/values for Cow
    unsafe {
        let animal_cow = &*random_animal(6);

        // Check that the struct's data is what we expect
        let data_ptr = data!(animal_cow);

        // Note: i8 ptr cast
        assert!(*(data_ptr as *mut i8) == 9); // From Cow

        let vtable_ptr = vtable!(animal_cow);

        // Drop pointer
        assert!(drop_from_vtable(vtable_ptr) == drop_in_place::<Cow> as *mut ());

        // Size and align as usizes
        assert!(size_from_vtable(vtable_ptr) == size_of::<i8>());
        assert!(align_from_vtable(vtable_ptr) == size_of::<i8>());
    }
}