pub trait AsyncWrite {
fn poll_write(
&mut self,
lw: &LocalWaker,
buf: &[u8]
) -> Poll<Result<usize, Error>>;
fn poll_flush(&mut self, lw: &LocalWaker) -> Poll<Result<(), Error>>;
fn poll_close(&mut self, lw: &LocalWaker) -> Poll<Result<(), Error>>;
fn poll_vectored_write(
&mut self,
lw: &LocalWaker,
vec: &[&IoVec]
) -> Poll<Result<usize, Error>> { ... }
}Write bytes asynchronously.
This trait is analogous to the std::io::Write trait, but integrates
with the asynchronous task system. In particular, the poll_write
method, unlike Write::write, will automatically queue the current task
for wakeup and return if data is not yet available, rather than blocking
the calling thread.
Attempt to write bytes from buf into the object.
On success, returns Ok(Async::Ready(num_bytes_written)).
If the object is not ready for writing, the method returns
Ok(Async::Pending) and arranges for the current task (via
lw.waker()) to receive a notification when the object becomes
readable or is closed.
This function may not return errors of kind WouldBlock or
Interrupted. Implementations must convert WouldBlock into
Async::Pending and either internally retry or convert
Interrupted into another error kind.
Attempt to flush the object, ensuring that any buffered data reach
their destination.
On success, returns Ok(Async::Ready(())).
If flushing cannot immediately complete, this method returns
Ok(Async::Pending) and arranges for the current task (via
lw.waker()) to receive a notification when the object can make
progress towards flushing.
This function may not return errors of kind WouldBlock or
Interrupted. Implementations must convert WouldBlock into
Async::Pending and either internally retry or convert
Interrupted into another error kind.
Attempt to close the object.
On success, returns Ok(Async::Ready(())).
If closing cannot immediately complete, this function returns
Ok(Async::Pending) and arranges for the current task (via
lw.waker()) to receive a notification when the object can make
progress towards closing.
This function may not return errors of kind WouldBlock or
Interrupted. Implementations must convert WouldBlock into
Async::Pending and either internally retry or convert
Interrupted into another error kind.
Attempt to write bytes from vec into the object using vectored
IO operations.
This method is similar to poll_write, but allows data from multiple buffers to be written
using a single operation.
On success, returns Ok(Async::Ready(num_bytes_written)).
If the object is not ready for writing, the method returns
Ok(Async::Pending) and arranges for the current task (via
lw.waker()) to receive a notification when the object becomes
readable or is closed.
By default, this method delegates to using poll_write on the first
buffer in vec. Objects which support vectored IO should override
this method.
This function may not return errors of kind WouldBlock or
Interrupted. Implementations must convert WouldBlock into
Async::Pending and either internally retry or convert
Interrupted into another error kind.