ArduinoCore API-integration, why is the AVR-core not using the classes HardwareI2C, HardwareSerial or HardwareSPI from the API?

[Guswib]

First of all, thank you all for all your hard work in the Arduino platform.

I have some questions regarding the ArduinoCore API integration of the AVR-core.

In ArduinoCore API there are the following classes: HardwareSPI, HardwareI2C and HardwareSerial. All of them are inheriting from the Stream-class.

1. Does anyone know why the classes TwoWire, SPI do not inherit from corresponding API-classes, but just inherit from Stream? Changing the inheritance should not break anything, but help with the standarization of function names.

2. Similarly, is there a reason why avr::HardwareSerial.h is not inherit from ArduinoAPI::HardwareSerial.h? It looks like most definitions in the avr-version is already expressed in the API.

3. Why is not SoftwareSerial-class also inherit from ArduinoAPI::HardwareSPI?

Thanks.