Salesforce Pub/Sub API Client

The `salesforce-pubsub-api-client` is a Node.js client library for interacting with the Salesforce Pub/Sub API, a gRPC-based event streaming service. Currently at stable version 5.5.2, it is actively maintained with frequent minor and patch releases, addressing bug fixes, dependency updates, and feature enhancements. The client abstracts the complexities of gRPC communication, offering multiple authentication flows (username/password, JWT bearer, client credentials), schema management for event data, and features like batch publishing and robust subscription management with replay IDs and flow control. A key differentiator in version 5 is its shift from an `EventEmitter`-based event handling model to a synchronous callback system, ensuring ordered event processing, and a simplified configuration approach via constructor options.