use crate::pack::data::File;use git_features::progress::Progress;use git_object::{owned, SHA1_SIZE}; #[derive(thiserror::Error, Debug)]pub enum Error {    #[error("pack checksum mismatch: expected {expected}, got {actual}")]    Mismatch { expected: owned::Id, actual: owned::Id },    #[error("could not read pack file")]    Io(#[from] std::io::Error),} /// Checksums and verify checksumsimpl File {    pub fn checksum(&self) -> owned::Id {        owned::Id::from_20_bytes(&self.data[self.data.len() - SHA1_SIZE..])    }    pub fn verify_checksum(&self, mut progress: impl Progress) -> Result<owned::Id, Error> {        let right_before_trailer = self.data.len() - SHA1_SIZE;        let actual = match crate::hash::bytes_of_file(&self.path, right_before_trailer, &mut progress) {            Ok(id) => id,            Err(_io_err) => {                let start = std::time::Instant::now();                let mut hasher = git_features::hash::Sha1::default();                hasher.update(&self.data[..right_before_trailer]);                progress.inc_by(right_before_trailer);                progress.show_throughput(start);                owned::Id::new_sha1(hasher.digest())            }        };         let expected = self.checksum();        if actual == expected {            Ok(actual)        } else {            Err(Error::Mismatch { actual, expected })        }    }}