Add LWT support

[sylwiaszunejko]

Fixes: #476, #475

[sylwiaszunejko]

@dkropachev This test keeps failing test_create_session_and_check_system_views_clients even though I haven't change any logic around it, do you have any idea why can this happen?

[dkropachev]

@dkropachev This test keeps failing test_create_session_and_check_system_views_clients even though I haven't change any logic around it, do you have any idea why can this happen?

It is some weird bug, it is also failing on my branch.

[dkropachev]

Great job, there are some minor changes needed

[dkropachev]

@sylwiaszunejko, you also forgot to address batch statement part, but before we go there, could you please run tests for all the cases from https://github.com/scylladb/scylla-drivers/issues/117 and post findings there, after we can discuss what API should look like.

[sylwiaszunejko]

@sylwiaszunejko, you also forgot to address batch statement part, but before we go there, could you please run tests for all the cases from scylladb/scylla-drivers#117 and post findings there, after we can discuss what API should look like.

WDYM by batch statements? AFAIU batch statement cannot be lwt or not as a whole

[dkropachev]

@sylwiaszunejko, you also forgot to address batch statement part, but before we go there, could you please run tests for all the cases from scylladb/scylla-drivers#117 and post findings there, after we can discuss what API should look like.

WDYM by batch statements? AFAIU batch statement cannot be lwt or not as a whole

They can have serial consistency, which means that they will work same way LWT statements work on the backend.
I know that if one statement of the batch is LWT then whole batch is going to have serial consistency.

[dkropachev]

@sylwiaszunejko, you also forgot to address batch statement part, but before we go there, could you please run tests for all the cases from scylladb/scylla-drivers#117 and post findings there, after we can discuss what API should look like.

WDYM by batch statements? AFAIU batch statement cannot be lwt or not as a whole

They can have serial consistency, which means that they will work same way LWT statements work on the backend. I know that if one statement of the batch is LWT then whole batch is going to have serial consistency.

Let's don't cover batch statements in this PR, we need to test how it works first

[dkropachev]

Small changes, rest looks good.

[dkropachev]

Last one, let's fix and merge