Valid version

0.9.13+

Debounce types

Type	Default	Algorithm	RAM usage	w/ Matrix scan	w/ Direct scan
:per_row	Yes	Symmetric eager debounce per row	Small	✔	🙅
:per_key	No	Symmetric eager debounce per key	Big	✔	✔
:none	No	No debounce	Almost zero	✔	✔

:per_key is the most recommended one unless your firmware causes an "Out of Memory" error
:per_row will not work well with :direct scan mode while it's the default one. Use :per_key instead. See [[Keyscan matrix]] abount scan modes
If you are confident your switches never bounce mechanically and you are a PC game enthusiast, use :none which doesn't cancel any bounce and performs maximum

kbd = Keyboard.new
kbd.set_debounce(:per_key)
kbd.set_debounce_threshold(70) # Optional. 40(ms) by default

If you didn't call set_debounce, :per_row debouncer will be used by default
When you'll call set_debounce_threshold, you should call set_debounce in advance even if you use the default :per_row algorithm