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use futures_task::{FutureObj, Spawn, SpawnError};
/// An implementation of [`Spawn`](futures_task::Spawn) that
/// discards spawned futures when used.
///
/// # Examples
///
/// ```
/// use futures::task::SpawnExt;
/// use futures_test::task::NoopSpawner;
///
/// let spawner = NoopSpawner::new();
/// spawner.spawn(async { }).unwrap();
/// ```
#[derive(Debug)]
pub struct NoopSpawner {
_reserved: (),
}
impl NoopSpawner {
/// Create a new instance
pub fn new() -> Self {
Self { _reserved: () }
}
}
impl Spawn for NoopSpawner {
fn spawn_obj(&self, _future: FutureObj<'static, ()>) -> Result<(), SpawnError> {
Ok(())
}
}
impl Default for NoopSpawner {
fn default() -> Self {
Self::new()
}
}
/// Get a reference to a singleton instance of [`NoopSpawner`].
///
/// # Examples
///
/// ```
/// use futures::task::SpawnExt;
/// use futures_test::task::noop_spawner_mut;
///
/// let spawner = noop_spawner_mut();
/// spawner.spawn(async { }).unwrap();
/// ```
pub fn noop_spawner_mut() -> &'static mut NoopSpawner {
Box::leak(Box::new(NoopSpawner::new()))
}