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: unix.rs
    path of file: ./repos/headcrab/src/target
    
    the code of the file until where you have to start completion: use nix::{
    sys::ptrace,
    sys::wait::{waitpid, WaitStatus},
    unistd::Pid,
};
use std::process::Command;

use crate::CrabResult;

/// This trait defines the common behavior for all *nix targets
pub trait UnixTarget {
    /// Provides the Pid of the debugee process
    fn pid(&self) -> Pid;

    /// Step the debuggee one instruction further.
    fn step(&self) -> CrabResult<Wa
    
pub(in crate::target) fn launch(mut cmd: Command) -> CrabResult<(Pid, WaitStatus)> {
    use std::os::unix::process::CommandExt;
    unsafe {
        cmd.pre_exec(|| {
            // Disable ASLR
            #[cfg(target_os = "linux")]
            {
                const ADDR_NO_RANDOMIZE: libc::c_ulong = 0x0040000;
                libc::personality(ADDR_NO_RANDOMIZE);
            }

            ptrace::traceme().map_err(|err| std::io::Error::new(std::io::ErrorKind::Other, err))?;

            Ok(())
        });
    }
    let child = cmd.spawn()?;
    let pid = Pid::from_raw(child.id() as i32);
    let status = waitpid(pid, None)?;
    Ok((pid, status))
}