fr.errDetail = errors.New(reason)
	return http2ConnectionError(code)
}

// checkFrameOrder reports an error if f is an invalid frame to return
// next from ReadFrame. Mostly it checks whether HEADERS and
// CONTINUATION frames are contiguous.
func (fr *http2Framer) checkFrameOrder(f http2Frame) error {
	last := fr.lastFrame
	fr.lastFrame = f
	if fr.AllowIllegalReads {
		return nil
	}