code: func NewArmor62DecoderStream(r io.Reader, hc HeaderChecker, fc FrameChecker) (io.Reader, Frame, error) {
  	return newArmorDecoderStream(r, Armor62Params, hc, fc)
  }
docs: // NewArmor62DecoderStream is used to decode input base62-armoring format. It returns
  // a stream you can read from, and also a Frame you can query to see what the open/close
  // frame markers were. hc and fc are optional and can be nil.