ProgressWorker.setContext(context) sets that the ProgressContext context should receive progress information when the run method in ProgressWorker is called.ProgressWorker.run(runnable) calls the run method on runnable on a separate thread and reports progress back to the registered ProgressContext.ProgressWorker.run(runnable, context) calls the run method on runnable on a separate thread and reports progress back to the ProgressContext context.