Trait Observer 

pub trait Observer: Send + Sync {
    // Required method
    fn on_event(&self, event: &Event);
}

Pluggable event sink. Multiple observers can subscribe to a single run.

Required Methods

fn on_event(&self, event: &Event)

Called for every event emitted during execution. Implementations should be cheap and non-blocking — a slow observer slows execution.

Implementors

impl Observer for CallbackManager

impl<F> Observer for F

where F: Fn(&Event) + Send + Sync,

Convenience: any Fn(&Event) + Send + Sync is an Observer.

impl<H: CallbackHandler> Observer for HandlerObserver<H>