Bulk Pubsub implementation in SDK

[mukundansundar]

Describe the proposal

Add SDK support for the new bulk Pub/Sub API runtime issue: dapr/dapr#2218

[dapr-bot]

This issue has been automatically marked as stale because it has not had activity in the last 60 days. It will be closed in the next 7 days unless it is tagged (pinned, good first issue, help wanted or triaged/resolved) or other activity occurs. Thank you for your contributions.

[berndverst]

@mukundansundar only maintainers should apply labels - please do not do that (even if it makes sense)

[berndverst]

@mukundansundar is there a SDK reference implementation for bulk pubsub yet? If so please link that here.

[mukundansundar]

For bulk publish
Java sdk dapr/java-sdk#789

JS SDK dapr/js-sdk#430

For bulk subscribe
JS SDK
dapr/js-sdk#437

[XavierGeerinck]

+1 on usage, currently doing it with the requests library but would be nice to be able to use the SDK with gRPC support

[berndverst]

When implementing this, please ensure to write a e2e test which verifies that publish metadata is actually applied to all items in a bulk publishing batch.

[sadath-12]

/assign

[sadath-12]

I'll get on this once the related issue gets fixed by my pr dapr/go-sdk#478