Single RxJava (and its derivatives like RxGroovy & RxScala) has developed an Observable variant called “Single.” RxJava(및 RxGroovy 및 RxScala와 같은 파생 제품)는 "Single"이라는 Observable 변형을 개발했습니다. A Single is something like an Observable, but instead of emitting a series of values — anywhere from none at all to an infinite number — it always either emits one value or an error notification. Single은 Observ..