Function subscribeToActivity

cli/src/utils/activity-tracker.ts:53–58

(callback: ActivityListener)

 * @returns Unsubscribe function
 */
export function subscribeToActivity(callback: ActivityListener): () => void {
  listeners.add(callback)
  return () => {
    listeners.delete(callback)
  }
}

/**
 * Reset the activity tracker (mainly for testing).