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: once_cell.rs
    path of file: ./repos/phaser/phaser/vendor/tokio/src/sync
    
    the code of the file until where you have to start completion: use super::{Semaphore, SemaphorePermit, TryAcquireError};
use crate::loom::cell::UnsafeCell;
use std::error::Error;
use std::fmt;
use std::future::Future;
use std::mem::MaybeUninit;
use std::ops::Drop;
use std::ptr;
use std::sync::atomic::{AtomicBool, Ordering};

// This file contains an implementation of an OnceCe
    
    fn set_value(&self, value: T, permit: SemaphorePermit<'_>) -> &T {
        // SAFETY: We are holding the only permit on the semaphore.
        unsafe {
            self.value.with_mut(|ptr| (*ptr).as_mut_ptr().write(value));
        }

        // Using release ordering so any threads that read a true from this
        // atomic is able to read the value we just stored.
        self.value_set.store(true, Ordering::Release);
        self.semaphore.close();
        permit.forget();

        // SAFETY: We just initialized the cell.
        unsafe { self.get_unchecked() }
    }