Method poll_next

datafusion-examples/examples/relation_planner/table_sample.rs:794–808

(
        mut self: Pin<&mut Self>,
        cx: &mut Context<'_>,
    )

    type Item = Result<RecordBatch>;

    fn poll_next(
        mut self: Pin<&mut Self>,
        cx: &mut Context<'_>,
    ) -> Poll<Option<Self::Item>> {
        match ready!(self.input.poll_next_unpin(cx)) {
            Some(Ok(batch)) => {
                let elapsed = self.metrics.elapsed_compute().clone();
                let _timer = elapsed.timer();
                let result = self.sampler.sample(&batch);
                Poll::Ready(Some(result.record_output(&self.metrics)))
            }
            Some(Err(e)) => Poll::Ready(Some(Err(e))),
            None => Poll::Ready(None),
        }
    }
}

impl RecordBatchStream for SampleStream {