pub fn seek_to_key(&mut self, key: KeySlice) -> Result<()> {
        let (blk_idx, blk_iter) = Self::seek_to_key_inner(&self.table, key)?;
        self.blk_iter = blk_iter;
        self.blk_idx = blk_idx;
        Ok(())
    }
Seek to the first key-value pair which >= `key`.
mini-lsm-mvcc/src/table/iterator.rs