Etherpad Socket.IO Load Test Client

`etherpad-load-test-socket-io` is a client library providing the core logic for programmatically load testing an Etherpad instance via its Socket.IO API. It simulates various user activities, such as "lurkers" (viewers) and "active authors" (editors), to gauge the performance and scalability of an Etherpad server. While this package provides the underlying client functionality, it is typically consumed by higher-level command-line tools, such as `etherpad-load-test`, which offer a more user-friendly interface for executing load tests. The current stable version is 1.0.3, with a Node.js engine requirement of `>=18.0.0`. Its release cadence aligns with the development of the `etherpad-load-test` CLI and the broader Etherpad project, focusing on stability and compatibility with Etherpad Lite. Its key differentiator is its direct, low-level interaction with Etherpad's Socket.IO protocol, enabling deep customization of load testing scenarios.