use crate::{hash::Write as HashWrite, loose};use std::io; /// Returned by [`loose::Object::verify_checksum()`]#[derive(thiserror::Error, Debug)]#[allow(missing_docs)]pub enum Error {    #[error("reading of object failed")]    Io(#[from] io::Error),    #[error("Decoding of object failed")]    Decode(#[from] super::decode::Error),    #[error("Object expected to have id {desired}, but actual id was {actual}")]    ChecksumMismatch {        desired: git_hash::ObjectId,        actual: git_hash::ObjectId,    },} impl loose::Object {    /// Generate the git hash of this object, reading it in the process, and compare it with the given `desired` [ObjectId][git_hash::ObjectId].    ///    /// Returns an error with the actual id if the hashes don't match.    pub fn verify_checksum(&mut self, desired: impl AsRef<git_hash::oid>) -> Result<(), Error> {        let desired = desired.as_ref();        let mut sink = HashWrite::new(io::sink(), desired.kind());        let (kind, size) = (self.kind, self.size);        let mut reader = self.stream()?;         loose::object::header::encode(kind, size as u64, &mut sink).expect("hash to always work");        io::copy(&mut reader, &mut sink)?;         let actual = git_hash::ObjectId::from(sink.hash.digest());        if desired != actual {            return Err(Error::ChecksumMismatch {                desired: desired.into(),                actual,            });        }        Ok(())    }}