I think we want to set these to client_name and client_version from the client if they are different from the previous task (or remain empty/unset if they are the same).

The PR description says "See temporalio/features#321" but this doesn't solve #588 completely. Is this just a temporary thing until #588 can be properly addressed?

Yes, that's right. There's a little bit more work and testing required for that because we need to be watching for changes from task-to-task, rather than sending the same value repeatedly. So that's #588. This PR is just for unblocking Typescript work so I was thinking that it's fine to merge this as-is since these changes will result in transmitting the protobuf default zero-values, which is what the server is already using.