fix errors about fmt and clippy
use num_cpus;
use std::cell::RefCell;
-use std::convert::TryInto;
-use std::io::{self, Error, ErrorKind, Read, Write};
+use std::ffi;
+use std::fs::File;
+use std::fs::OpenOptions;
+use std::io::{self, ErrorKind, Read, Write};
#[cfg(unix)]
use std::os::unix::fs::OpenOptionsExt;
#[cfg(windows)]
use std::os::windows::fs::OpenOptionsExt;
-use std::ffi;
-use std::fs::File;
-use std::fs::OpenOptions;
use std::time::{Duration, SystemTime};
use std::{env, fs};
