pub async fn filter_written_slots(&mut self, hashed_keys: &[H256]) -> DalResult<HashSet<H256>> {
        let hashed_keys: Vec<_> = hashed_keys.iter().map(H256::as_bytes).collect();
        Ok(sqlx::query!(
            r#"
            SELECT
                hashed_key
            FROM
                initial_writes
            WHERE
                hashed_key = ANY($1)
            "#,
            &hashed_keys as &[&[u8]],
        )
        .instrument("filter_written_slots")
        .with_arg("hashed_keys.len", &hashed_keys.len())
        .fetch_all(self.storage)
        .await?
        .into_iter()
        .map(|row| H256::from_slice(&row.hashed_key))
        .collect())
    }
Returns `hashed_keys` that are both present in the input and in `initial_writes` table.
core/lib/dal/src/storage_logs_dedup_dal.rs