[feature request] Support publish messages to partitioned topics

[yash2]

Could we provide support for node clients to publish messages partition topics,

• So publishing messages to partitioned topics, can specify a routing mode. If we not specify any routing mode then round-robin routing mode should be used.

Reference docs supporting the functionality for other client libraries: https://pulsar.apache.org/docs/next/client-libraries-producers/#publish-messages-to-partitioned-topics

[merlimat]

Client is based on C++ lib which already supports publishing to partitioned topics transparently.

The routing mode can be selected with the messageRoutingMode property when creating the producer.

[BewareMyPower]

Currently the default routing mode is single-partition in the underlying C++ client by default.

Node.js client provides the option to switch the routing mode, see

pulsar-client-node/index.d.ts

Line 55 in 2d659d2

messageRoutingMode?: MessageRoutingMode;

[shibd]

@yash2 Do you want Customize message router for Node.js client?