Allow updating memo during workflow execution

[longquanzheng]

Is your feature request related to a problem? Please describe.

Memo now is passed when StartWF, and can be retrieved during execution. However, it is not allowed to change. It will be much more useful if it's allowed to change and user can use it as a k-v store. When reading the value, Descrbie API will return the result with strongly consistency. In that way people can get rid of the query task(and handler implementation) for some small kv data.

Proposed Solution

1. Add a new field in RespondDecisionTaskCompletedRequest to allow passing new memo data.
2. Add a new field in DecisionTaskCompletedEventAttributes to record the memo change
3. Process it to update the memo.

Additional context

Related to https://github.com/uber-go/cadence-client/issues/1033

[ychensha]

any update?

[demirkayaender]

We haven't looked into this issue yet but might work on it later this year. We are planning to go over all the github issues sometime around July and prioritize them.

[longquanzheng]

It's already supported in Temporal (goSDK): https://github.com/temporalio/sdk-go/releases/tag/v1.17.0

[edmondop]

@longquanzheng is there a typo in the issue description? I think you mean "it is not allowed to change" not "it is now allowed to change"

[longquanzheng]

@longquanzheng is there a typo in the issue description? I think you mean "it is not allowed to change" not "it is now allowed to change"

Ahh right! Thanks. Just fixed it