Update Tokio to Rust 2018 (#1082)

tokio-fs/src/write.rs

@@ -1,7 +1,7 @@
-use futures::{Async, Future, Poll};
+use crate::{file, File};
+use futures::{try_ready, Async, Future, Poll};
 use std::{fmt, io, mem, path::Path};
 use tokio_io;
-use {file, File};
 
 /// Creates a future that will open a file for writing and write the entire
 /// contents of `contents` to it.
@@ -11,20 +11,19 @@ use {file, File};
 /// # Examples
 ///
 /// ```no_run
-/// # extern crate tokio;
 /// use tokio::prelude::Future;
-/// fn main() {
-///     let buffer = b"Hello world!";
-///     let task = tokio::fs::write("foo.txt", buffer).map(|data| {
-///         // `data` has now been written to foo.txt. The buffer is being
-///         // returned so it can be used for other things.
-///         println!("foo.txt now had {} bytes written to it", data.len());
-///     }).map_err(|e| {
-///         // handle errors
-///         eprintln!("IO error: {:?}", e);
-///     });
-///     tokio::run(task);
-/// }
+///
+/// let buffer = b"Hello world!";
+/// let task = tokio::fs::write("foo.txt", buffer).map(|data| {
+///     // `data` has now been written to foo.txt. The buffer is being
+///     // returned so it can be used for other things.
+///     println!("foo.txt now had {} bytes written to it", data.len());
+/// }).map_err(|e| {
+///     // handle errors
+///     eprintln!("IO error: {:?}", e);
+/// });
+///
+/// tokio::run(task);
 /// ```
 pub fn write<P, C: AsRef<[u8]>>(path: P, contents: C) -> WriteFile<P, C>
 where