Function run_metadata_git 

pub fn run_metadata_git(
    real_git: &Path,
    arguments: &[OsString],
    overlay: &[(OsString, OsString)],
) -> Result<MetadataOutput>

What: Run real Git with captured output and no standard input. std::io::Result<T> is Result<T, std::io::Error>. Why: A query must never consume the caller’s stdin (which belongs to the forwarded command) or write to the caller’s streams.

In TS you’d write (pseudocode):

async function runMetadataGit(realGit, args, overlay): Promise<MetadataOutput>;