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: iovec.rs
    path of file: ./repos/firecracker/src/vmm/src/devices/virtio
    
    the code of the file until where you have to start completion: // Copyright 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved.
// SPDX-License-Identifier: Apache-2.0

use std::io::ErrorKind;

use libc::{c_void, iovec, size_t};
use smallvec::SmallVec;
use vm_memory::{
    GuestMemoryError, Re
    
    fn create_iovecs(mem: *mut u8, size: usize) -> (IoVecVec, usize) {
        let nr_descs: usize = kani::any_where(|&n| n <= MAX_DESC_LENGTH);
        let mut vecs: Vec<iovec> = Vec::with_capacity(nr_descs);
        let mut len = 0usize;
        for _ in 0..nr_descs {
            // The `IoVecBuffer(Mut)` constructors ensure that the memory region described by every
            // `Descriptor` in the chain is a valid, i.e. it is memory with then guest's memory
            // mmap. The assumption, here, that the last address is within the memory object's
            // bound substitutes these checks that `IoVecBuffer(Mut)::new() performs.`
            let addr: usize = kani::any();
            let iov_len: usize =
                kani::any_where(|&len| matches!(addr.checked_add(len), Some(x) if x <= size));
            let iov_base = unsafe { mem.offset(addr.try_into().unwrap()) } as *mut c_void;

            vecs.push(iovec { iov_base, iov_len });
            len += iov_len;
        }

        (vecs, len)
    }