Full runnable example for the documentation https://zio.dev/docs/datatypes/stream/subscription-ref including correcting the type inference for IDEA

ZioSubscriptionRef.scala

import java.io.IOException

import zio.{Chunk, RefM, Runtime, UIO, URIO, ZIO, console, random}
import zio.console.Console
import zio.random.Random
import zio.stream.{SubscriptionRef, ZStream}

// Full running example for the ZIO documentation https://zio.dev/docs/datatypes/stream/subscription-ref
object Subscription extends App {

  val runtime: Runtime[zio.ZEnv] = Runtime.default

  def server(ref: RefM[Long]): UIO[Nothing] =
    ref.update[Any, Nothing](n => ZIO.succeed(n + 1)).forever

  def client(changes: ZStream[Any, Nothing, Long]): URIO[Random, Chunk[Long]] =
    for {
      n     <- random.nextLongBetween(1, 200)
      chunk <- changes.take(n).runCollect
    } yield chunk

  val app: ZIO[Console with Random, IOException, Unit] = for {
    subscriptionRef <- SubscriptionRef.make(0L)
    server          <- server(subscriptionRef.ref).fork
    chunks          <- ZIO.collectAllPar(List.fill(100)(client(subscriptionRef.changes)))
    _               <- server.interrupt
    _               <- ZIO.foreach(chunks)(chunk => console.putStrLn(chunk.toString))
  } yield ()
  print(runtime.unsafeRun(app))
}