CBS_peek_asn1_tag
if (CBS_peek_asn1_tag(cbs, tag)) {
int CBS_peek_asn1_tag(const CBS *cbs, unsigned int tag_value);
if (CBS_peek_asn1_tag(cbs, tag)) {
int CBS_peek_asn1_tag(const CBS *cbs, unsigned int tag_value);
CHECK(!CBS_peek_asn1_tag(&data, 0x1));
CHECK(CBS_peek_asn1_tag(&data, 0x30));
CHECK(!CBS_peek_asn1_tag(&data, 0x30));