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: faulty_ctl.rs
    path of file: ./repos/zbox/src/volume/storage
    
    the code of the file until where you have to start completion: use std::io::{Error as IoError, ErrorKind, Result as IoResult};
use std::sync::{Arc, RwLock};

use lazy_static::lazy_static;

use crate::base::crypto::{Crypto, RandomSeed};

lazy_static! {
    // static variable to store random samples
    static ref ERR_CONTEXT: Arc<RwLock<ErrorCont
    
    pub fn make_random_error(&self) -> IoResult<()> {
        let mut context = ERR_CONTEXT.write().unwrap();
        if !context.is_on {
            return Ok(());
        }

        assert!(!context.samples.is_empty());
        let idx = context.sample_seq % context.samples.len();
        context.sample_seq += 1;

        let sample = context.samples[idx];
        match sample {
            _ if sample <= context.threshold => {
                Err(IoError::new(ErrorKind::Other, "Faulty error"))
            }
            _ => Ok(()),
        }
    }