Function parse_git_signature 

pub fn parse_git_signature(
    raw: &[u8],
    commit: &str,
    field: &str,
) -> Result<GitImportSignature, HeddleError>

Parse a raw Git author/committer value for commit, preserving what reconstruction needs for a byte-identical commit (the -0000 timezone sign). Identities that cannot be reconstructed exactly are rejected with an error naming the commit and the header, never imported lossily:

• no <email>;
• a timestamp outside the range DateTime<Utc> can hold;
• an empty name written with a separating space (author <e> …), since a State records only the empty name and rebuilds it as author <e> ….