public Builder addTag(String tag) {
            if (!ClickHouseChecker.isNullOrEmpty(tag)) {
                tags.add(tag);
            }

            return this;
        }
Adds a tag for this node.

@param tag tag for the node, null or duplicate tag will be ignored
@return this builder
clickhouse-client/src/main/java/com/clickhouse/client/ClickHouseNode.java