Async receive (feature)

[micw]

Hi,
I think about adding an async receive feature. Since receiving is already interrupt-driven, it should not be that hard - onle the channel swtching code needs to be done in a timer interrupt. I'll test it on my STM32 module, maybe also on ESP8266. But I don't know if it can be done on Arduino as well (I don't have those boards here).
Regards,
Michael.