In the scala monix package. when i subscribe. how to Avoid using sleep?

Question

Complete all data processing and close the program in time. ! not use sleep? how can i do?

Although sleep will be blocked to achieve the purpose of data processing, I cannot set a reasonable time, too small will lead to data processing cannot be completed, too large and can not bear too long.

package org.apache.spark.sql.catalyst.json.com

import zio.ZIO
import monix.eval._
import monix.execution.Callback
import monix.execution.Scheduler

import scala.concurrent.duration.DurationInt
import monix.reactive._
import monix.execution.Scheduler.Implicits.global

import java.lang.Thread.sleep
import scala.util.Random


object ScalaZIOLearn1 {

    def main(args: Array[String]): Unit = {


        val t: Observable[Task[Int]] = {
            Observable
                .fromIterable[Int](11 to 2200000 toIterable)
                .asyncBoundary(OverflowStrategy.BackPressure(3))
                //                .interval(1.second)
                // common filtering and mapping
                .map {
                    x =>
                        println(s"map1 ${x}")
                        sleep(Random.nextInt(3000))
                        x + 10000
                }
                .asyncBoundary(OverflowStrategy.BackPressure(3))
                .map { x =>
                    println(s"map2 ${x}")
                    sleep(Random.nextInt(3000))
                    x * 10
                }
                .map { x =>
                    Task {
                        //                    println(s"flatmap: ${x}")
                        println(s"map3 ${x} start")
                        sleep(15000)
                        println(s"map3 ${x} end")
                        x
                    }
                }
        }
        t.subscribe()


        sleep(Long.MaxValue)  // its not smart.  can you have other method?  Complete all data processing and close the program in time. !

    }


}