You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: cargo.rs
    path of file: ./repos/llvm-cov-pretty/src
    
    the code of the file until where you have to start completion: use std::process::Command;

use camino::{Utf8Path, Utf8PathBuf};
use color_eyr
    
pub fn project_dir(manifest_path: Option<&Utf8Path>) -> Result<Utf8PathBuf> {
    let manifest_path = match manifest_path {
        Some(path) => path.to_owned(),
        None => cargo_locate_project().wrap_err("failed to locate project")?,
    };

    cargo_metadata(&manifest_path)
        .map(|meta| meta.workspace_root)
        .wrap_err("failed to load project metadata")
}