Type Alias AsyncWriteCallbackFuture 

pub type AsyncWriteCallbackFuture<'a> = Pin<Box<dyn Future<Output = Result<()>> + Send + 'a>>;

Type alias for async write callback return type.

We use a boxed future for callbacks. The future is Send since internal operations use Arc/Mutex for thread-safety.

Aliased Type

pub struct AsyncWriteCallbackFuture<'a> { /* private fields */ }