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: output.rs
    path of file: ./repos/mdcat/src
    
    the code of the file until where you have to start completion: // Copyright 2020 Sebastian Wiesner <sebastian@swsnr.de>

// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this
// file, You can obtain one at http://mozilla.org/MPL/2.0/.

use std::io::Write;
use std::process::*;

use anyhow::{bail, Context, Result};
use tracing::{event, Level};

/// The output for mdcat
pub enum Output {
    /// St
    
fn pager_from_env() -> Result<Vec<String>> {
    for envvar in ["MDCAT_PAGER", "PAGER"] {
        event!(Level::TRACE, envvar, "looking for pager in environment");
        match parse_env_var(envvar) {
            // Continue looking
            Ok(None) => {}
            Ok(Some(command)) => {
                event!(Level::INFO, envvar, "Using {:?} as pager", command);
                return Ok(command);
            }
            Err(error) => {
                event!(Level::ERROR, envvar, %error, "Parsing failed: {:#}", error);
                return Err(error);
            }
        }
    }
    event!(Level::DEBUG, "Falling back to default pager less -r");
    Ok(vec!["less".into(), "-r".into()])
}