So you have to add code to debug it with #tap? I don’t care if the chain is unbroken: you have to CHANGE THE CODE YOU SHIPPED in order to properly debug it. That’s idiotic. And before you say “oh, this is just an exercise”, I can tell you from personal experience that I encounter this endlessly in prod code with both Python and Kotlin chained functional style garbage. It is often not debuggable without break-up and unrolling.