shepmaster

    low_level_result.context(ErrorWithContextSnafu { context })?;
    low_level_result.map_err(|err| CustomError::ErrorWithContext { err, context })?;

    #[derive(Debug, Snafu)]
    struct DemoError { source: std::io::Error, filename: PathBuf }

    let filename: &Path = todo!();
    result.context(OpenFileSnafu { filename })?; // `context` will change `&Path` to `PathBuf`

    #[error("failed to open a: {0}")]