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: builders.rs
    path of file: ./repos/fern/src
    
    the code of the file until where you have to start completion: use std::{
    borrow::Cow,
    cmp, fmt, fs, io,
    io::Write,
    sync::{mpsc::Sender, Arc, Mutex},
};

#[cfg(feature = "
    
/// # fn setup_logger() -> Result<(), fern::InitError> {
/// fern::Dispatch::new()
///     .format(|out, message, record| {
///         out.finish(format_args!(
///             "[{} {}] {}",
///             record.level(),
///             record.target(),
///             message,
///         ))
///     })
///     .chain(
///         fern::Dispatch::new()
///             // by default only accept warn messages
///             .level(log::LevelFilter::Warn)
///             // accept info messages from the current crate too
///             .level_for("my_crate", log::LevelFilter::Info)
///             // `io::Stdout`, `io::Stderr` and `io::File` can be directly passed in.
///             .chain(io::stdout()),
///     )
///     .chain(
///         fern::Dispatch::new()
///             // output all messages
///             .level(log::LevelFilter::Trace)
///             // except for hyper, in that case only show info messages
///             .level_for("hyper", log::LevelFilter::Info)
///             // `log_file(x)` equates to
///             // `OpenOptions::new().write(true).append(true).create(true).open(x)`
///             .chain(fern::log_file("persistent-log.log")?)
///             .chain(
///                 fs::OpenOptions::new()
///                     .write(true)
///                     .create(true)
///                     .truncate(true)
///                     .create(true)
///                     .open("/tmp/temp.log")?,
///             ),
///     )
///     .chain(
///         fern::Dispatch::new()
///             .level(log::LevelFilter::Error)
///             .filter(|_meta_data| {
///                 // as an example, randomly reject half of the messages
///                 # /*
///                 rand::random()
///                 # */
///                 # true
///             })
///             .chain(io::stderr()),
///     )
///     // and finally, set as the global logger!
///     .apply()?;
/// # Ok(())
/// # }