Interesting... I'm actively using the Write method, but for emitting console messages using constant strings. Anyway, thanks

It seems to me that I found the answer (was googling for two hours and found nothing, then used forum search and voila):

1. Declare a class which inherits Ens.Production:

Class My.Production Extends Ens.Production
{

XData ProductionDefinition
{
<Production Name="My.Production" TestingEnabled="true" LogGeneralTraceEvents="true">
  <Description></Description>
  <ActorPoolSize>1</ActorPoolSize>
</Production>
}
}

2. And launch:

Set isProductionRunning = ##class(Ens.Director).IsProductionRunning("My.Production")
If isProductionRunning = 0 {
            Set sc = ##class(Ens.Director).StartProduction("My.Production")
}

Ended up with a compromise 😊 Just replaced <transform> with a <call> and delegated that transform to BO