pub(crate) async fn next_block(&self, ctx: &ctx::Ctx) -> ctx::Result<validator::BlockNumber> {
        Ok(sync::lock(ctx, &self.block_payloads)
            .await?
            .as_ref()
            .context("payload_queue not set")?
            .next())
    }
Number of the next block to queue.
core/node/consensus/src/storage/store.rs