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use core::marker;
use {Future, Poll, Async};
/// A future representing a finished successful computation.
///
/// Created by the `finished` function.
#[must_use = "futures do nothing unless polled"]
pub struct Finished<T, E> {
t: Option<T>,
_e: marker::PhantomData<E>,
}
/// Creates a "leaf future" from an immediate value of a finished and
/// successful computation.
///
/// The returned future is similar to `done` where it will immediately run a
/// scheduled callback with the provided value.
///
/// # Examples
///
/// ```
/// use futures::*;
///
/// let future_of_1 = finished::<u32, u32>(1);
/// ```
pub fn finished<T, E>(t: T) -> Finished<T, E> {
Finished { t: Some(t), _e: marker::PhantomData }
}
impl<T, E> Future for Finished<T, E> {
type Item = T;
type Error = E;
fn poll(&mut self) -> Poll<T, E> {
Ok(Async::Ready(self.t.take().expect("cannot poll Finished twice")))
}
}