Allow subclassing

[pennam]

Apply after #21 and remember to change base banch to main

[github-actions]

Memory usage change @ 3525b0f

Board	flash	%	RAM for global variables	%
arduino:esp32:nano_nora	💚 -64 - 0	-0.0 - 0.0	💚 -8 - 0	-0.0 - 0.0
esp32:esp32:esp32	💚 -56 - 0	-0.0 - 0.0	💚 -16 - 0	-0.0 - 0.0

Click for full report table

Board	examples/OTA_Arduino_Server flash	%	examples/OTA_Arduino_Server RAM for global variables	%	examples/OTA_GitHub_Server flash	%	examples/OTA_GitHub_Server RAM for global variables	%	examples/NANO_ESP32_Blink flash	%	examples/NANO_ESP32_Blink RAM for global variables	%	examples/LOLIN_32_Blink flash	%	examples/LOLIN_32_Blink RAM for global variables	%
arduino:esp32:nano_nora	-64	-0.0	-8	-0.0	-64	-0.0	-8	-0.0	0	0.0	0	0.0
esp32:esp32:esp32	-56	-0.0	-16	-0.0	-56	-0.0	-16	-0.0					0	0.0	0	0.0

Click for full report CSV

Board,examples/OTA_Arduino_Server<br>flash,%,examples/OTA_Arduino_Server<br>RAM for global variables,%,examples/OTA_GitHub_Server<br>flash,%,examples/OTA_GitHub_Server<br>RAM for global variables,%,examples/NANO_ESP32_Blink<br>flash,%,examples/NANO_ESP32_Blink<br>RAM for global variables,%,examples/LOLIN_32_Blink<br>flash,%,examples/LOLIN_32_Blink<br>RAM for global variables,%
arduino:esp32:nano_nora,-64,-0.0,-8,-0.0,-64,-0.0,-8,-0.0,0,0.0,0,0.0
esp32:esp32:esp32,-56,-0.0,-16,-0.0,-56,-0.0,-16,-0.0,,,,,0,0.0,0,0.0