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: io.rs
    path of file: ./repos/vector/lib/vector-buffers/src/variants/disk_v2
    
    the code of the file until where you have to start completion: use std::{io, path::Path};

use async_trait::async_trait;
use tokio::{
    fs::OpenOptions,
    io::{AsyncRead, AsyncWrite},
};

#[cfg(unix)]
const FILE_MODE_OWNER_RW_GROUP_RO: u32 = 0o640;

/// File metadata.
pub 
    
fn create_writable_file_options(create_atomic: bool) -> OpenOptions {
    let mut open_options = open_writable_file_options();

    #[cfg(unix)]
    {
        open_options.mode(FILE_MODE_OWNER_RW_GROUP_RO);
    }

    if create_atomic {
        open_options.create_new(true);
    } else {
        open_options.create(true);
    }

    open_options
}