pub fn delete(self: &Arc<Self>, key: &[u8]) -> Result<()> {
        if !self.options.serializable {
            self.write_batch_inner(&[WriteBatchRecord::Del(key)])?;
        } else {
            let txn = self.mvcc().new_txn(self.clone(), self.options.serializable);
            txn.delete(key);
            txn.commit()?;
        }
        Ok(())
    }
Remove a key from the storage by writing an empty value.
mini-lsm-mvcc/src/lsm_storage.rs