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: Sage_fifo.rs
    path of file: ./repos/sniprun/src/interpreters
    
    the code of the file until where you have to start completion: #[derive(Clone)]
#[allow(non_camel_case_types)]
pub struct Sage_fifo {
    support_level: SupportLevel,
    data: DataHolder,
    code: String,
    imports: String,
    main_file_path: String,
    cache_dir: String,

    interpreter: String,
    current_output_id: u32,
    user_sage_config: bool,
}

impl Sage_fifo {
    fn wait_out_file(
        &self,
        out_path: String,
        err_path: String,
        id: u32,
    ) -> Result<String, SniprunError> {
        let end_mark = String::from("sniprun_finished_id=") + &id.to_string() + "\n";
        let start_mark = String::from("sniprun_started_id=") + &id.to_string();

        info!(
            "searching for things between {:?} and {:?}",
            start_mark, end_mark
        );

        let mut out_contents = String::new();
        let mut err_contents = String::new();

        let mut pause = std::time::Duration::from_millis(50);
        let _start = std::time::Instant::now();
        loop {
            std::thread::sleep(pause);
            pause = pause.saturating_add(std::time::Duration::from_millis(50));

            //check for stderr first
            if let Ok(mut file) =
    
    fn add_boilerplate_repl(&mut self) -> Result<(), SniprunError> {
        self.add_boilerplate()?;
        let start_mark = String::from("\n\nprint(\"sniprun_started_id=")
            + &self.current_output_id.to_string()
            + "\")\n\n";
        let end_mark = String::from("\n\nprint(\"sniprun_finished_id=")
            + &self.current_output_id.to_string()
            + "\")\n\n";
        let start_mark_err = String::from("\nprint(\"sniprun_started_id=")
            + &self.current_output_id.to_string()
            + "\", file=sys.stderr)\n";
        let end_mark_err = String::from("\nprint(\"sniprun_finished_id=")
            + &self.current_output_id.to_string()
            + "\", file=sys.stderr)\n";

        // remove empty lines interpreted as 'enter' by the sage interpreter
        self.code = self
            .code
            .lines()
            .filter(|l| !l.trim().is_empty())
            .collect::<Vec<&str>>()
            .join("\n");

        let all_code = self.imports.clone() + "\n" + &self.code + "\n";
        self.code = String::from("\nimport sys\n\n")
            + &start_mark
            + &start_mark_err
            + &all_code
            + &end_mark
            + &end_mark_err;
        Ok(())
    }