/**
* @param numThreads Num of threads for this worker pool.
* @param filePath A file path with implementation of `ThreadWorker` class, relative path is fine.
* @param opts An object with possible options for example `errorHandler`, `onlineHandler`. Default: `{ maxTasks: 1000 }`
*/
/**
* @param numThreads Num of threads for this worker pool.
* @param filePath A file path with implementation of `ThreadWorker` class, relative path is fine.
* @param opts An object with possible options for example `errorHandler`, `onlineHandler`. Default: `{ maxTasks: 1000 }`
*/