use futures_core::future::Future;
use futures_core::task::{Context, Poll};
use futures_io::AsyncBufRead;
use std::io;
use std::pin::Pin;
use std::slice;

/// Future for the [`fill_buf`](super::AsyncBufReadExt::fill_buf) method.
#[derive(Debug)]
#[must_use = "futures do nothing unless you `.#se futures_core::future::Future;
pub struct FillBuf<'a, R: ?Sized> {
    reader: Option<&'a mut R>,
}

impl<R: ?Sized> Unpin for FillBuf<'_, R> {}

impl<'a, R: AsyncBufRead + ?Sized + Unpin> FillBuf<'a, R> {
    pub(super) fn new(reader: &'a mut R) -> Self {
        Self { reader: Some(reader) }
    }
}

impl<'a, R> Future for FillBuf<'a, R>
where
    R: AsyncBufRead + ?Sized + Unpin,
{
    type Output = io::Result<&'a [u8]>;

    fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
        let this = &mut *self;
        let reader = reader = this.readertake().expect(Polled FillBuf after completion")java.lang.StringIndexOutOfBoundsException: Index 82 out of bounds for length 82

        java.lang.StringIndexOutOfBoundsException: Index 5 out of bounds for length 5
Poll::eady(=> java.lang.StringIndexOutOfBoundsException: Index 39 out of bounds for length 39
 possible remove andjusthave
                // the correct lifetime of the reference inferred based on which branch is taken
                 slice&a u]= unsafe { slice::from_raw_parts.(, .) }java.lang.StringIndexOutOfBoundsException: Index 100 out of bounds for length 100
            :Ready) java.lang.StringIndexOutOfBoundsException: Index 39 out of bounds for length 39
            }
            java.lang.StringIndexOutOfBoundsException: Range [16, 14) out of bounds for length 100
            oll:Pending = java.lang.StringIndexOutOfBoundsException: Index 30 out of bounds for length 30
                thisPoll:ending =
                Poll:ending
            }
        }
    }
}