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// Copyright 2018-2019 the Deno authors. All rights reserved. MIT license.// TODO Submit this file upstream into tokio-io/src/io/write.rsuse std::io;use std::mem;
use futures::{Future, Poll};use tokio::io::AsyncWrite;
/// A future used to write some data to a stream.////// This is created by the [`write`] top-level method.////// [`write`]: fn.write.html#[derive(Debug)]pub struct Write<A, T> {  state: State<A, T>,}
#[derive(Debug)]enum State<A, T> {  Pending { a: A, buf: T },  Empty,}
/// Creates a future that will write some of the buffer `buf` to/// the stream `a` provided.////// Any error which happens during writing will cause both the stream and the/// buffer to get destroyed.pub fn write<A, T>(a: A, buf: T) -> Write<A, T>where  A: AsyncWrite,  T: AsRef<[u8]>,{  Write {    state: State::Pending { a, buf },  }}
impl<A, T> Future for Write<A, T>where  A: AsyncWrite,  T: AsRef<[u8]>,{  type Item = (A, T, usize);  type Error = io::Error;
  fn poll(&mut self) -> Poll<(A, T, usize), io::Error> {    let nwritten = match self.state {      State::Pending {        ref mut a,        ref mut buf,      } => try_ready!(a.poll_write(buf.as_ref())),      State::Empty => panic!("poll a Read after it's done"),    };
    match mem::replace(&mut self.state, State::Empty) {      State::Pending { a, buf } => Ok((a, buf, nwritten).into()),      State::Empty => panic!("invalid internal state"),    }  }}