# tokio::io::BufStream - Rust
API documentation for the Rust `BufStream` struct in crate `tokio`.
Keywords: rust, rustlang, rust-lang, BufStream

# Struct tokio::io::BufStream [−] [src]

    pub struct BufStream<RW> { /* fields omitted */ }

Wraps a type that is `AsyncWrite` and `AsyncRead`, and buffers its input and output.

It can be excessively inefficient to work directly with something that implements `AsyncWrite` and `AsyncRead`. For example, every `write`, however small, has to traverse the syscall interface, and similarly, every read has to do the same. The `BufWriter` and `BufReader` types aid with these problems respectively, but do so in only one direction. `BufStream` wraps one in the other so that both directions are buffered. See their documentation for details.

## Implementations

### `impl<RW: AsyncRead + AsyncWrite> BufStream<RW>` [src]

#### `pub fn new(stream: RW) -> BufStream<RW>` [src]

Wraps a type in both `BufWriter` and `BufReader`.

See the documentation for those types and `BufStream` for details.

#### `pub fn with_capacity(
reader_capacity: usize,
writer_capacity: usize,
stream: RW
) -> BufStream<RW>` [src]

Creates a `BufStream` with the specified `BufReader` capacity and `BufWriter` capacity.

See the documentation for those types and `BufStream` for details.

#### `pub fn get_ref(&self) -> &RWⓘ

### Notable traits for &'_ mut F

`impl<'_, F> Future for &'_ mut F where
F: Unpin + Future + ?Sized, type Output = <F as Future>::Output;`
` [src]

Gets a reference to the underlying I/O object.

It is inadvisable to directly read from the underlying I/O object.

#### `pub fn get_mut(&mut self) -> &mut RWⓘ

### Notable traits for &'_ mut F

`impl<'_, F> Future for &'_ mut F where
F: Unpin + Future + ?Sized, type Output = <F as Future>::Output;`
` [src]

Gets a mutable reference to the underlying I/O object.

It is inadvisable to directly read from the underlying I/O object.

#### `pub fn get_pin_mut(self: Pin<&mut Self>) -> Pin<&mut RW>ⓘ

### Notable traits for Pin<P>

`impl<P> Future for Pin<P> where
P: Unpin + DerefMut,
<P as Deref>::Target: Future, type Output = <<P as Deref>::Target as Future>::Output;`
` [src]

Gets a pinned mutable reference to the underlying I/O object.

It is inadvisable to directly read from the underlying I/O object.

#### `pub fn into_inner(self) -> RW` [src]

Consumes this `BufStream`, returning the underlying I/O object.

Note that any leftover data in the internal buffer is lost.

## Trait Implementations

### `impl<RW: AsyncRead + AsyncWrite> AsyncBufRead for BufStream<RW>` [src]

#### `fn poll_fill_buf(
self: Pin<&mut Self>,
cx: &mut Context<'_>
) -> Poll<Result<&[u8]>>` [src]

Attempts to return the contents of the internal buffer, filling it with more data from the inner reader if it is empty. Read more

#### `fn consume(self: Pin<&mut Self>, amt: usize)` [src]

Tells this buffer that `amt` bytes have been consumed from the buffer, so they should no longer be returned in calls to `poll_read`. Read more

### `impl<RW: AsyncRead + AsyncWrite> AsyncRead for BufStream<RW>` [src]

#### `fn poll_read(
self: Pin<&mut Self>,
cx: &mut Context<'_>,
buf: &mut ReadBuf<'_>
) -> Poll<Result<()>>` [src]

Attempts to read from the `AsyncRead` into `buf`. Read more

### `impl<RW: AsyncRead + AsyncWrite> AsyncWrite for BufStream<RW>` [src]

#### `fn poll_write(
self: Pin<&mut Self>,
cx: &mut Context<'_>,
buf: &[u8]
) -> Poll<Result<usize>>` [src]

Attempt to write bytes from `buf` into the object. Read more

#### `fn poll_flush(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<()>>` [src]

Attempts to flush the object, ensuring that any buffered data reach their destination. Read more

#### `fn poll_shutdown(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<()>>` [src]

Initiates or attempts to shut down this writer, returning success when the I/O connection has completely shut down. Read more

#### `fn poll_write_vectored(
self: Pin<&mut Self>,
cx: &mut Context<'_>,
bufs: &[IoSlice<'_>]
) -> Poll<Result<usize, Error>>` [src]

Like `poll_write`, except that it writes from a slice of buffers. Read more

#### `fn is_write_vectored(&self) -> bool` [src]

Determines if this writer has an efficient `poll_write_vectored` implementation. Read more

### `impl<RW: Debug> Debug for BufStream<RW>` [src]

#### `fn fmt(&self, f: &mut Formatter<'_>) -> Result` [src]

Formats the value using the given formatter. Read more

### `impl<RW> From<BufReader<BufWriter<RW>>> for BufStream<RW>` [src]

#### `fn from(b: BufReader<BufWriter<RW>>) -> Self` [src]

Performs the conversion.

### `impl<RW> From<BufWriter<BufReader<RW>>> for BufStream<RW>` [src]

#### `fn from(b: BufWriter<BufReader<RW>>) -> Self` [src]

Performs the conversion.

### `impl<'__pin, RW> Unpin for BufStream<RW> where
__Origin<'__pin, RW>: Unpin,` [src]

## Auto Trait Implementations

### `impl<RW> RefUnwindSafe for BufStream<RW> where
RW: RefUnwindSafe,` [src]

### `impl<RW> Send for BufStream<RW> where
RW: Send,` [src]

### `impl<RW> Sync for BufStream<RW> where
RW: Sync,` [src]

### `impl<RW> UnwindSafe for BufStream<RW> where
RW: UnwindSafe,` [src]

## Blanket Implementations

### `impl<T> Any for T where
T: 'static + ?Sized,` [src]

#### `pub fn type_id(&self) -> TypeId` [src]

Gets the `TypeId` of `self`. Read more

### `impl<T> Borrow<T> for T where
T: ?Sized,` [src]

#### `pub fn borrow(&self) -> &Tⓘ

### Notable traits for &'_ mut F

`impl<'_, F> Future for &'_ mut F where
F: Unpin + Future + ?Sized, type Output = <F as Future>::Output;`
` [src]

Immutably borrows from an owned value. Read more

### `impl<T> BorrowMut<T> for T where
T: ?Sized,` [src]

#### `pub fn borrow_mut(&mut self) -> &mut Tⓘ

### Notable traits for &'_ mut F

`impl<'_, F> Future for &'_ mut F where
F: Unpin + Future + ?Sized, type Output = <F as Future>::Output;`
` [src]

Mutably borrows from an owned value. Read more

### `impl<T> From<T> for T` [src]

#### `pub fn from(t: T) -> T` [src]

Performs the conversion.

### `impl<T, U> Into<U> for T where
U: From<T>,` [src]

#### `pub fn into(self) -> U` [src]

Performs the conversion.

### `impl<T, U> TryFrom<U> for T where
U: Into<T>,` [src]

#### `type Error = Infallible`

The type returned in the event of a conversion error.

#### `pub fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>` [src]

Performs the conversion.

### `impl<T, U> TryInto<U> for T where
U: TryFrom<T>,` [src]

#### `type Error = <U as TryFrom<T>>::Error`

The type returned in the event of a conversion error.

#### `pub fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>` [src]

Performs the conversion.