
    @ProtobufProperty(index = 9, type = UINT64)
    private Long recipientTimestamp;

    @ProtobufProperty(index = 10, type = UINT32, repeated = true, packed = true)
    private List<Integer> recipientKeyIndexes;

    public static class DeviceListMetadataBuilder {
        public DeviceListMetadataBuilder senderKeyIndexes(List<Integer> senderKeyIndexes) {
            if (this.senderKeyIndexes == null) this.senderKeyIndexes = new ArrayList<>();
            this.senderKeyIndexes.addAll(senderKeyIndexes);
            return this;
        }