pub trait Operator: Send {
    // Required method
    fn on_element<'life0, 'life1, 'async_trait>(
        &'life0 mut self,
        ctx: &'life1 mut dyn Context,
        record: Record,
    ) -> Pin<Box<dyn Future<Output = Result<()>> + Send + 'async_trait>>
       where Self: 'async_trait,
             'life0: 'async_trait,
             'life1: 'async_trait;
    // Provided methods
    fn on_watermark<'life0, 'life1, 'async_trait>(
        &'life0 mut self,
        _ctx: &'life1 mut dyn Context,
        _wm: Watermark,
    ) -> Pin<Box<dyn Future<Output = Result<()>> + Send + 'async_trait>>
       where Self: 'async_trait,
             'life0: 'async_trait,
             'life1: 'async_trait { ... }
    fn on_timer<'life0, 'life1, 'async_trait>(
        &'life0 mut self,
        _ctx: &'life1 mut dyn Context,
        _when: EventTime,
        _key: Option<Vec<u8>>,
    ) -> Pin<Box<dyn Future<Output = Result<()>> + Send + 'async_trait>>
       where Self: 'async_trait,
             'life0: 'async_trait,
             'life1: 'async_trait { ... }
}Expand description
Core operator interface. Override on_watermark/on_timer if needed.