Struct AsyncOnceCell

pub struct AsyncOnceCell<T> { /* private fields */ }

This structure contains a cell for a single value. The cell can be written only once, and can be read many times. Readers are provided with async API, that waits for write to happen. This is similar to tokio::sync::watch, except one difference:

• tokio::sync::watch requires existing receiver to work. If no subscriber is registered, and the value is sent to channel, the value is dropped
• Unlike with tokio::sync::watch, it is possible to write to AsyncOnceCell when no readers are registered, and value will be available later when AsyncOnceCell::get is called

Implementations

impl<T: Send + Clone> AsyncOnceCell<T>

pub fn new() -> Self

pub async fn get(&self) -> T

pub fn set(&self, value: T) -> Result<(), ()>

Sets the value and notifies waiters. Return error if called twice

Trait Implementations

impl<T: Send + Clone> Default for AsyncOnceCell<T>

fn default() -> Self

Returns the “default value” for a type.