public void
restore() {
	if (saved_pos < 0) {
		throw new IllegalStateException("no previous state");
	}
	byteBuffer.position(saved_pos);
	byteBuffer.limit(saved_end);
	saved_pos = -1;
	saved_end = -1;
}
Restores the input stream to its state before the call to {@link #save}.
src/main/java/core/org/xbill/DNS/DNSInput.java