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: connect.rs
    path of file: ./repos/async-postgres/src
    
    the code of the file until where you have to start completion: #[cfg(unix)]
use async_std::os::unix::net::UnixStream;

use crate::Socket;
use async_std::io;
use async_std::net::TcpStream;
use std::future::Future;
use std::time::Duration;
use tokio_postgres::config
    
/// async fn play() -> Result<(), Box<dyn Error>> {
///     let cert = fs::read("database_cert.pem")?;
///     let cert = Certificate::from_pem(&cert)?;
///     let connector = TlsConnector::builder()
///         .add_root_certificate(cert)
///         .build()?;
///     let connector = MakeTlsConnector::new(connector);
///     let url = "host=localhost user=postgres sslmode=require";
///     let (client, conn) = connect_tls(url.parse()?, connector).await?;
///     spawn(conn);
///     let row = client.query_one("SELECT * FROM user WHERE id=$1", &[&0]).await?;
///     let value: &str = row.get(0);
///     println!("value: {}", value);
///     Ok(())
/// }