var buf bytes.Buffer
	e := json.NewEncoder(&buf)
	d := jstream.NewDecoder(r, 0).ObjectAsKVS()
	sset := set.NewStringSet()
	for mv := range d.Stream() {
		var kvs jstream.KVS
		if mv.ValueType == jstream.Object {
			// This is a JSON object type (that preserves key order)
			kvs = mv.Value.(jstream.KVS)
			for _, kv := range kvs {
				if sset.Contains(kv.Key) {
					// Reject duplicate conditions or expiration.