[feature request] Support Key-based batcher

[shibd]

Motivation

C++ client already supports. The node.js client just needs to expose the configuration.

[joshua-motorq]

Is there any update on this?

If i am correct, the default is not key based batching. And

in https://pulsar.apache.org/docs/next/concepts-messaging/#batching-for-key_shared-subscriptions

When the consumers are using the Key_Shared subscription type, you need to disable batching or use key-based batching for the producers.

So i am assuming there has to be a way where we can use a key based batching for the producer. Can i please be pointed to it?

[joshua-motorq]

@shibd Are you aware of any way to achieve this?

[shibd]

We only need to expose this configuration. The C++ client that the Node.js client kernel depends on already supports it.