Struct tracing_core::stdlib::task::ContextBuilder

pub struct ContextBuilder<'a> {
    waker: &'a Waker,
    local_waker: &'a LocalWaker,
    ext: ExtData<'a>,
    _marker: PhantomData<fn(_: &'a ()) -> &'a ()>,
    _marker2: PhantomData<*mut ()>,
}

🔬This is a nightly-only experimental API. (local_waker #118959)

A Builder used to construct a Context instance with support for LocalWaker.

Examples

#![feature(local_waker)]
#![feature(noop_waker)]
use std::task::{ContextBuilder, LocalWaker, Waker, Poll};
use std::future::Future;

let local_waker = LocalWaker::noop();
let waker = Waker::noop();

let mut cx = ContextBuilder::from_waker(&waker)
    .local_waker(&local_waker)
    .build();

let mut future = std::pin::pin!(async { 20 });
let poll = future.as_mut().poll(&mut cx);
assert_eq!(poll, Poll::Ready(20));

Fields

waker: &'a Waker

🔬This is a nightly-only experimental API. (local_waker #118959)

local_waker: &'a LocalWaker

🔬This is a nightly-only experimental API. (local_waker #118959)

ext: ExtData<'a>

🔬This is a nightly-only experimental API. (local_waker #118959)

_marker: PhantomData<fn(_: &'a ()) -> &'a ()>

🔬This is a nightly-only experimental API. (local_waker #118959)

_marker2: PhantomData<*mut ()>

🔬This is a nightly-only experimental API. (local_waker #118959)

Implementations

impl<'a> ContextBuilder<'a>

pub const fn from_waker(waker: &'a Waker) -> ContextBuilder<'a>

🔬This is a nightly-only experimental API. (local_waker #118959)

Create a ContextBuilder from a Waker.

pub const fn from(cx: &'a mut Context<'_>) -> ContextBuilder<'a>

🔬This is a nightly-only experimental API. (context_ext #123392)

Create a ContextBuilder from an existing Context.

pub const fn waker(self, waker: &'a Waker) -> ContextBuilder<'a>

🔬This is a nightly-only experimental API. (context_ext #123392)

This method is used to set the value for the waker on Context.

pub const fn local_waker( self, local_waker: &'a LocalWaker, ) -> ContextBuilder<'a>

🔬This is a nightly-only experimental API. (local_waker #118959)

This method is used to set the value for the local waker on Context.

pub const fn ext(self, data: &'a mut (dyn Any + 'static)) -> ContextBuilder<'a>

🔬This is a nightly-only experimental API. (context_ext #123392)

This method is used to set the value for the extension data on Context.

pub const fn build(self) -> Context<'a>

🔬This is a nightly-only experimental API. (local_waker #118959)

Builds the Context.

Trait Implementations

impl<'a> Debug for ContextBuilder<'a>

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.