Reformat imports to a consistent style for imports

rustfmt.toml configuration:
  imports_granularity = "One"
  group_imports = "One"

perf/src/cuda_runtime.rs

@@ -5,23 +5,26 @@
 //    copies from host memory to GPU memory unless the memory is page-pinned and
 //    cannot be paged to disk. The cuda driver provides these interfaces to pin and unpin memory.
 
-use crate::perf_libs;
-use crate::recycler::{RecyclerX, Reset};
-use rand::seq::SliceRandom;
-use rand::Rng;
-use rayon::prelude::*;
-use std::ops::{Index, IndexMut};
-use std::slice::{Iter, IterMut, SliceIndex};
-use std::sync::Weak;
-
-use std::os::raw::c_int;
+use {
+    crate::{
+        perf_libs,
+        recycler::{RecyclerX, Reset},
+    },
+    rand::{seq::SliceRandom, Rng},
+    rayon::prelude::*,
+    std::{
+        ops::{Index, IndexMut},
+        os::raw::c_int,
+        slice::{Iter, IterMut, SliceIndex},
+        sync::Weak,
+    },
+};
 
 const CUDA_SUCCESS: c_int = 0;
 
 fn pin<T>(_mem: &mut Vec<T>) {
     if let Some(api) = perf_libs::api() {
-        use std::ffi::c_void;
-        use std::mem::size_of;
+        use std::{ffi::c_void, mem::size_of};
 
         let ptr = _mem.as_mut_ptr();
         let size = _mem.capacity().saturating_mul(size_of::<T>());