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use std::future::Future;

/// Convert a type into a `Future`.

///

/// # Examples

///

/// ```

/// use async_std::future::{Future, IntoFuture};

/// use async_std::io;

/// use async_std::pin::Pin;

///

/// struct Client;

///

/// impl Client {

///     pub async fn send(self) -> io::Result<()> {

///         // Send a request

///         Ok(())

///     }

/// }

///

/// impl IntoFuture for Client {

///     type Output = io::Result<()>;

///

///     type Future = Pin<Box<dyn Future<Output = Self::Output>>>;

///

///     fn into_future(self) -> Self::Future {

///         Box::pin(async {

///             self.send().await

///         })

///     }

/// }

/// ```

#[cfg(feature = "unstable")]
#[cfg_attr(feature = "docs", doc(cfg(unstable)))]
pub trait IntoFuture {
    /// The type of value produced on completion.

    type Output;

    /// Which kind of future are we turning this into?

    type Future: Future<Output = Self::Output>;

    /// Create a future from a value

    fn into_future(self) -> Self::Future;
}

impl<T: Future> IntoFuture for T {
    type Output = T::Output;
    type Future = T;

    fn into_future(self) -> Self::Future {
        self
    }
}