thanks, <@U9DPCUAB0>. it turns out that Firebase e...

# rx

[ubu]

thanks, @ursus. it turns out that Firebase emits callback on the main thread no matter what, and my AsyncTransformer gets ignored, which is why I need to put observeOn() multiple times. I no longer have that clear APi with only AsynTransformer dealing with threads, but that's okay.