Struct async_buf::buf_writer::BufWriter
source · [−]pub struct BufWriter<W> { /* private fields */ }
Expand description
Wraps a writer and buffers its output.
It can be excessively inefficient to work directly with something that
implements Write
. For example, every call to
write
on TcpStream
results in a system call. A
BufWriter
keeps an in-memory buffer of data and writes it to an underlying
writer in large, infrequent batches.
BufWriter
can improve the speed of programs that make small and
repeated write calls to the same file or network socket. It does not
help when writing very large amounts at once, or writing just one or a few
times. It also provides no advantage when writing to a destination that is
in memory, like a Vec<u8>
.
Unlike the BufWriter
type in std
, this type does not write out the
contents of its buffer when it is dropped. Therefore, it is absolutely
critical that users explicitly flush the buffer before dropping a
BufWriter
.
This type is an async version of std::io::BufWriter
.
Examples
Implementations
sourceimpl<W> BufWriter<W>
impl<W> BufWriter<W>
sourcepub fn new(inner: W) -> BufWriter<W>
pub fn new(inner: W) -> BufWriter<W>
Creates a new BufWriter
with a default buffer capacity. The default is currently 8 KB,
but may change in the future.
Examples
sourcepub fn with_capacity(capacity: usize, inner: W) -> BufWriter<W>
pub fn with_capacity(capacity: usize, inner: W) -> BufWriter<W>
Creates a new BufWriter
with the specified buffer capacity.
Examples
sourceimpl<W: AsyncWrite> BufWriter<W>
impl<W: AsyncWrite> BufWriter<W>
sourcepub async fn into_inner(self) -> Result<W, IntoInnerError<BufWriter<W>>> where
Self: Unpin,
pub async fn into_inner(self) -> Result<W, IntoInnerError<BufWriter<W>>> where
Self: Unpin,
Consumes BufWriter
, returning the underlying writer
This method will not write leftover data, it will be lost.
For method that will attempt to write before returning the writer see poll_into_inner
Examples
Trait Implementations
sourceimpl<W: AsyncWrite> AsyncWrite for BufWriter<W>
impl<W: AsyncWrite> AsyncWrite for BufWriter<W>
sourcefn poll_write(
self: Pin<&mut Self>,
cx: &mut Context<'_>,
buf: &[u8]
) -> Poll<Result<usize>>
fn poll_write(
self: Pin<&mut Self>,
cx: &mut Context<'_>,
buf: &[u8]
) -> Poll<Result<usize>>
Attempt to write bytes from buf
into the object. Read more
sourcefn poll_flush(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<()>>
fn poll_flush(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<()>>
Attempt to flush the object, ensuring that any buffered data reach their destination. Read more
impl<'__pin, W> Unpin for BufWriter<W> where
__Origin<'__pin, W>: Unpin,
Auto Trait Implementations
impl<W> RefUnwindSafe for BufWriter<W> where
W: RefUnwindSafe,
impl<W> Send for BufWriter<W> where
W: Send,
impl<W> Sync for BufWriter<W> where
W: Sync,
impl<W> UnwindSafe for BufWriter<W> where
W: UnwindSafe,
Blanket Implementations
sourceimpl<W> AsyncWriteExt for W where
W: AsyncWrite + ?Sized,
impl<W> AsyncWriteExt for W where
W: AsyncWrite + ?Sized,
sourcefn write(&'a mut self, buf: &'a [u8]) -> WriteFuture<'a, Self> where
Self: Unpin,
fn write(&'a mut self, buf: &'a [u8]) -> WriteFuture<'a, Self> where
Self: Unpin,
Writes some bytes into the byte stream. Read more
sourcefn write_vectored(
&'a mut self,
bufs: &'a [IoSlice<'a>]
) -> WriteVectoredFuture<'a, Self> where
Self: Unpin,
fn write_vectored(
&'a mut self,
bufs: &'a [IoSlice<'a>]
) -> WriteVectoredFuture<'a, Self> where
Self: Unpin,
sourcefn write_all(&'a mut self, buf: &'a [u8]) -> WriteAllFuture<'a, Self> where
Self: Unpin,
fn write_all(&'a mut self, buf: &'a [u8]) -> WriteAllFuture<'a, Self> where
Self: Unpin,
Writes an entire buffer into the byte stream. Read more
sourcefn flush(&mut self) -> FlushFuture<'_, Self> where
Self: Unpin,
fn flush(&mut self) -> FlushFuture<'_, Self> where
Self: Unpin,
Flushes the stream to ensure that all buffered contents reach their destination. Read more
sourcefn close(&mut self) -> CloseFuture<'_, Self> where
Self: Unpin,
fn close(&mut self) -> CloseFuture<'_, Self> where
Self: Unpin,
Closes the writer. Read more
sourcefn boxed_writer<'a>(self) -> Pin<Box<dyn AsyncWrite + Send + 'a, Global>> where
Self: 'a + Send,
fn boxed_writer<'a>(self) -> Pin<Box<dyn AsyncWrite + Send + 'a, Global>> where
Self: 'a + Send,
Boxes the writer and changes its type to dyn AsyncWrite + Send + 'a
. Read more
sourceimpl<T> BorrowMut<T> for T where
T: ?Sized,
impl<T> BorrowMut<T> for T where
T: ?Sized,
const: unstable · sourcefn borrow_mut(&mut self) -> &mut T
fn borrow_mut(&mut self) -> &mut T
Mutably borrows from an owned value. Read more