Method poll_next

datafusion/core/tests/custom_sources_cases/mod.rs:121–131

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

    type Item = Result<RecordBatch>;

    fn poll_next(
        self: Pin<&mut Self>,
        _cx: &mut Context<'_>,
    ) -> Poll<Option<Self::Item>> {
        if self.nb_batch > 0 {
            self.get_mut().nb_batch -= 1;
            Poll::Ready(Some(TEST_CUSTOM_RECORD_BATCH!().map_err(Into::into)))
        } else {
            Poll::Ready(None)
        }
    }
}

impl DisplayAs for CustomExecutionPlan {