* wifi: ARP gratuitous API for wifi station mode
* fix with lwip1
* update comment
* update API to allow changing interval on the fly
* update API
* remove debug lines
* mock lwIP's etharp_request()
* unsigned interval
* use scheduled ticker
* ticker: +attach_ms_scheduled_accurate
ticker: +comment
gratuitous: use attach_ms_scheduled_accurate
* move to experimental namespace
* fix for lwIP-v1.4
* attempt to make pio happy
* use directly ETSTimer instead of Ticker
* Backport from ESP32
* Use new library layout (.../src)
* Cleanup test case.
* C++ style cast required.
* Whitespace
* Inlining via header has better baseline ROM footprint.
* Reordered functions for better code-compare to master
* Reduces ROM footprint some more.
* Avoid unnecessary parameter passing - refactoring, same generated footprint.
* Reformat example sources