Add Schedule and Functional/Scheduled Ticker

[hreintke]

Identical implementation as in ESP8266

[me-no-dev]

How about this to get written in more ESP32 and RTOS style? Use a thread (start it on first call of schedule) instead of attaching always to the loop ;)

[hreintke]

@me-no-dev
I have no problem doing it that way but then the functionality of the ESP32 & ESP8266 is fundamental different.
1/ the one-to-one loop/scheduled rhythm is lost
2/ as the scheduled functions would run in a separate thread, all needs to be thread safe

BTW, there is additional activity in the ESP8266 esp8266/Arduino#4609

Just let me know which way you want to go and I will provide a proposal.

[me-no-dev]

I understand, but this is a dual-core chip which runs an actual OS, so let's make it run as it should. ESP8266 runs NonOS like most other MCUs.

[hreintke]

@me-no-dev See PR #1516

[fabianoriccardi]

no hope about this PR? It would be great porting some old esp8266 program without messing up with different "API"

[CLAassistant]

Thank you for your submission! We really appreciate it. Like many open source projects, we ask that you sign our Contributor License Agreement before we can accept your contribution.
_{You have signed the CLA already but the status is still pending? Let us recheck it.}