Fix batch_put ttl issue

[limbooverlambda]

There is a bug in the client where the ttls are not properly sharded for RawBatchPuts. This essentially means that if the batch is spread across multiple regions, the ttls for the batch specific to the shard is not properly aligned. This is an issue when the request ends up in the TiKV node specific to the region and fails because of the misalignment of the Vec<TTLs> with its corresponding Vec<KvPair>. The fix was to change the sharding logic for RawBatchPutRequest so that the TTLs are aligned with the KvPair. Maintaining a mapping of the kvpair to its corresponding ttl in the Shard output.

• Added unit tests for the batch_put
• Ran integ tests to confirm:

warning: `tikv-client` (lib) generated 4 warnings (run `cargo fix --lib -p tikv-client` to apply 2 suggestions)
    Finished `test` profile [unoptimized + debuginfo] target(s) in 0.61s
     Running tests/integration_tests.rs (target/debug/deps/integration_tests-ae58f87a6b1272e6)

running 26 tests
test raw_bank_transfer ... ok
test raw_req ... ok
test txn_crud ... ok
test txn_batch_mutate_optimistic ... ok
test raw_ttl ... ok
test raw_cas ... ok
test txn_bank_transfer ... ok
test txn_batch_mutate_pessimistic ... ok
test txn_get_for_update ... ok
test raw_write_million ... ok
test txn_get_timestamp ... ok
test txn_insert_duplicate_keys ... ok
test txn_key_exists ... ok
test txn_lock_keys ... ok
test txn_lock_keys_error_handle ... ok
test txn_pessimistic ... ok
test txn_pessimistic_delete ... ok
test txn_pessimistic_heartbeat ... ok
test txn_pessimistic_rollback ... ok
test txn_read ... ok
test txn_scan ... ok
test txn_scan_reverse ... ok
test txn_scan_reverse_multi_regions ... ok
test txn_split_batch ... ok
test txn_unsafe_destroy_range ... ok
test txn_update_safepoint ... ok

test result: ok. 26 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 60.74s

[pingyu]

store_stream_for_keys is able to handle data of keys along with values and ttls. Mapping by Hash map is not necessary, and it's not efficient as well.

Please refer to PrewriteRequest::shards.

[limbooverlambda]

Thanks for the review. Didn't realize store_stream_for_keys has this capability. Removed the HashMap to collect the ttls for the kv_pair.

[limbooverlambda]

Hi @pingyu, I have made the changes. Please let me know if there's anything else I need to consider for this PR.

[pingyu]

Rest LGTM.

[limbooverlambda]

Thanks for helping me clean up this PR @pingyu. Addressed your comments.

[pingyu]

I'm sorry I missed another suggestion in last comments. The clone in comparation should also be un-necessary.

[pingyu]

Suggested change

[limbooverlambda]

done.

[pingyu]

Suggested change

	kv_ttl.sort_by(|a, b| a.0.key.clone().cmp(&b.0.key));
	kv_ttl.sort_by(|a, b| a.0.key.cmp(&b.0.key));

[limbooverlambda]

Removed.

[limbooverlambda]

I'm sorry I missed another suggestion in last comments. The clone in comparation should also be un-necessary.

Yeah, I should have caught that. Removed.

[pingyu]

LGTM~
Thanks for you contribution !