-use std::time::Duration;
-use std::sync::{Mutex, Arc};
-use std::sync::atomic::{AtomicBool, AtomicUsize, Ordering};
-use std::{cmp, mem};
-use std::collections::{HashMap, HashSet, VecDeque};
+use prelude::*;
+use core::time::Duration;
+use sync::{Mutex, Arc};
+use core::sync::atomic::{AtomicBool, AtomicUsize, Ordering};
+use core::{cmp, mem};