[feat][txn]Implement transactional consumer/producer API

[liangyepianzhou]

Master Issue:#932

Motivation

Implement transaction coordinator client.

Modifications

1. Implement transaction coordinator
2. implement transactionImpl
3. Implement transaction in producer and consumer API

Verifying this change

• Make sure that the change passes the CI checks.

(Please pick either of the following options)

This change is a trivial rework / code cleanup without any test coverage.

(or)

This change is already covered by existing tests, such as (please describe tests).

(or)

This change added tests and can be verified as follows:

(example:)

• Added integration tests for end-to-end deployment with large payloads (10MB)
• Extended integration test for recovery after broker failure

Does this pull request potentially affect one of the following parts:

If yes was chosen, please highlight the changes

• Dependencies (does it add or upgrade a dependency): (yes / no)
• The public API: (yes / no)
• The schema: (yes / no / don't know)
• The default values of configurations: (yes / no)
• The wire protocol: (yes / no)

Documentation

• Does this pull request introduce a new feature? (yes / no)
• If yes, how is the feature documented? (not applicable / docs / GoDocs / not documented)
• If a feature is not applicable for documentation, explain why?
• If a feature is not documented yet in this PR, please create a followup issue for adding the documentation

[shibd]

Is this the last PR about transactions? It's better to add some sample code to examples.

[liangyepianzhou]

Is this the last PR about transactions? It's better to add some sample code to examples.

Yes, this is the last PR concerning transactions. In the tests I've added, I've only used the API to perform the tests, which can serve as an initial example. Adding more detailed examples to the documentation might be more appropriate?

[shibd]

Adding more detailed examples to the documentation might be more appropriate?

Yes, the documentation can be described step by step, and complete examples are placed in the examples folder. We can push in a later PR.

[Anonymitaet]

Hi @liangyepianzhou thanks for introducing this great feature!

========================================

As we discussed just now, for the doc side:

✅ Pulsar feature matrix

I've ticked the three boxes (client, producer, consumer) of "Transactions" for Go.

✅ Pulsar client docs

1. Could you please provide the tech inputs as below?

   Add Go code example to Transactions > Get started .

2. This feature is available from Pulsar 2.9.5, can we add the doc to 4 doc versions (NEXT, 2.11.x, 2.10.x, 2.9.x) or just indicate what version it supports?

   • For 2.9.x: we can add a tip to the 2.9.x doc and indicate that this feature is available from (or in) Pulsar 2.9.5.
   • For 2.11.x and 2.10.x: please see the questions below.

BTW,

• Original doc file of NEXT is here.
• Original doc files of all versioned docs are here.

========================================

Feel free to reach out to me if you have questions. TIA!

[liangyepianzhou]

Could you please retake a look? @BewareMyPower @shibd

[shibd]

Could you please retake a look? @BewareMyPower @shibd

Sorry, I'll take a look at it today.

[shibd]

Overall LGTM, left some small comments.