code: func (k *Kite) FinalFunc(f FinalFunc) {
  	k.finalFuncs = append(k.finalFuncs, f)
  }
docs: // FinalFunc registers a function that is always called as a last one
  // after pre-, handler and post- functions.
  //
  // It receives a result and an error from last handler that
  // got executed prior to calling final func.