    fn get_memory_usage(&self) -> usize {
            mem::size_of::<Vec<T>>() + self.capacity() * mem::size_of::<T>()
    }
}

impl MemoryUsage for LargeBlock {
    fn get_memory_usage(&self) -> usize {
        mem::size_of::<u64>() * 2
    }
}

impl MemoryUsage for LastBlock {