mapAsync 类型不匹配； 找到：所需单位：scala.concurrent.Future

Question

My this piece of code complaining about type mismatch; found: Unit required: scala.concurrent.Future type mismatch; found: Unit required: scala.concurrent.Future , whereas I am returning a Future . I am very new in Scala not sure what I am missing here .

val records: List[CommittableRecord[Either[Throwable, MyEvent]]] = ???
records.mapAsync(1){ x => 
        val res = (x.value match {
          case Right(event:MyEvent) =>  
              val future = getTask(event.get("task").getOrElse(""))
              //future => Future[Try[Int]]
              val k = future.map {                  
                   case Success(value) => value 
                   case Failure(exception) => 0                   
              }
              //k => Future[Int]
        })
      }

Answer 1

变量赋值返回Unit ，只需删除val k =或将k放在最后