Function tokio_util::io::poll_read_buf [−][src]
pub fn poll_read_buf<T: AsyncRead, B: BufMut>(
io: Pin<&mut T>,
cx: &mut Context<'_>,
buf: &mut B
) -> Poll<Result<usize>>
This is supported on crate feature
io
only.Expand description
Try to read data from an AsyncRead
into an implementer of the BufMut
trait.
Example
use bytes::{Bytes, BytesMut}; use tokio_stream as stream; use tokio::io::Result; use tokio_util::io::{StreamReader, poll_read_buf}; use futures::future::poll_fn; use std::pin::Pin; // Create a reader from an iterator. This particular reader will always be // ready. let mut read = StreamReader::new(stream::iter(vec![Result::Ok(Bytes::from_static(&[0, 1, 2, 3]))])); let mut buf = BytesMut::new(); let mut reads = 0; loop { reads += 1; let n = poll_fn(|cx| poll_read_buf(Pin::new(&mut read), cx, &mut buf)).await?; if n == 0 { break; } } // one or more reads might be necessary. assert!(reads >= 1); assert_eq!(&buf[..], &[0, 1, 2, 3]);