Callback for showKeyboard?

Hi. It would be nice with a callback for showKeyboard, to know when the keyboard is hidden. I mean when you press the hide key on the keyboard.

showKeyboard(function () 
  -- called when hidden

Currently I have to solve it by implementing a handler in my Scene class like this:

function Scene:showKeyboard(hideCallback)
  if self.hideCallback then self.hideCallback() end
  self.hideCallback = hideCallback

But I don’t know that the keyboard was hidden before it’s shown again for another object I clicked on.