public ServerSetsRegistrationSpecBuilder sequential(boolean sequential) {
        this.sequential = sequential;
        return this;
    }
Sets whether to create the ZooKeeper node using {@link CreateMode#EPHEMERAL_SEQUENTIAL} or not.
The default value is {@code true} that means the node will be created sequentially by appending
the sequence number to {@link #nodeName(String)}. For example, if the {@code nodeName} is
{@code "foo_"}, the nodes will be {@code "foo_0000000000"}, {@code "foo_0000000001"} and so on.
zookeeper3/src/main/java/com/linecorp/armeria/server/zookeeper/ServerSetsRegistrationSpecBuilder.java