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: str_beu32_codec.rs
    path of file: ./repos/meilisearch/milli/src/heed_codec
    
    the code of the file until where you have to start completion: use std::borrow::Cow;
use std::convert::TryInto;
use std::mem::size_of;
use std::str;

use heed::BoxedError;

use super::SliceTooShortError;

pub struct StrBEU32Codec;

impl<'a> heed::BytesDecode<'a> for StrBEU32Codec {
 
    
    fn bytes_decode(bytes: &'a [u8]) -> Result<Self::DItem, BoxedError> {
        let footer_len = size_of::<u16>();

        if bytes.len() < footer_len + 1 {
            return Err(SliceTooShortError.into());
        }

        let (word_plus_nul_byte, bytes) = bytes.split_at(bytes.len() - footer_len);
        // unwrap: we just checked the footer + 1 above.
        let (_, word) = word_plus_nul_byte.split_last().unwrap();
        let word = str::from_utf8(word)?;
        let pos = bytes.try_into().map(u16::from_be_bytes)?;

        Ok((word, pos))
    }