code: func (i *FSTIterator) Reset(f *FST,
  	startKeyInclusive, endKeyExclusive []byte, aut Automaton) error {
  	if aut == nil {
  		aut = alwaysMatchAutomaton
  	}
  
  	i.f = f
  	i.startKeyInclusive = startKeyInclusive
  	i.endKeyExclusive = endKeyExclusive
  	i.aut = aut
  
  	return i.pointTo(startKeyInclusive)
  }
docs: // Reset resets the Iterator' internal state to allow for iterator
  // reuse (e.g. pooling).