Problem with Laminar StrictSignal.foldLeft where the accumulated value is an EventStream

gistfile1.txt

import com.raquo.laminar.api.L.*
import munit.FunSuite

import scala.collection.mutable

case class Foo(s: String)
case class Bar(s: String)

object Interpreter {
  def interpret(foo: Foo): EventStream[Bar]                       = EventStream.fromValue(Bar(foo.s))
  def interpretAndReconcile(foo: Foo, bar: Bar): EventStream[Bar] = EventStream.fromValue(Bar(s"${foo.s}(${bar.s})"))
}

class SignalTransformer extends FunSuite {
  def transform(foos: StrictSignal[Foo], owner: Owner): EventStream[Bar] = {
    val queue         = mutable.Queue.empty[Foo]
    val fooToProcess  = new EventBus[Foo]
    val bars          = Var[Option[Bar]](None)
    var shouldDequeue = true

    def dequeueNext(): Unit =
      if (shouldDequeue && queue.nonEmpty) {
        shouldDequeue = false
        fooToProcess.writer.onNext(queue.dequeue())
      }

    def doFirst(foo: Foo): Unit = {
      Interpreter
        .interpret(foo)
        .foreach { bar =>
          bars.writer.onNext(Some(bar))
          shouldDequeue = true
          dequeueNext()
        }(owner)
      ()
    }

    def doSubsequent(acc: Bar, foo: Foo) = {
      Interpreter
        .interpretAndReconcile(foo, acc)
        .foreach { bar =>
          bars.writer.onNext(Some(bar))
          shouldDequeue = true
          dequeueNext()
        }(owner)
      ()
    }

    fooToProcess.events.foreach { foo =>
      bars
        .now()
        .fold(doFirst(foo))(currentBar => doSubsequent(currentBar, foo))
    }(owner)

    foos.foreach { foo =>
      queue.enqueue(foo)
      dequeueNext()
    }(owner)

    EventStream.merge(EventStream.fromValue(bars.now()), bars.signal.changes).collect { case Some(bar) => bar }
  }

  test("StrictSignal") {
    val foo1: Foo = Foo("1")
    val foo2: Foo = Foo("2")
    val foo3: Foo = Foo("3")

    val $foo: Var[Foo] = Var(foo1)

    transform($foo.signal, unsafeWindowOwner).foreach(bar => println(bar))(unsafeWindowOwner)

    $foo.set(foo2)
    $foo.set(foo3)
  }
}