@Override
    public String asString() {
        if (bytes != null && value == null) {
            value = new String(bytes, StandardCharsets.UTF_8);
        }

        return value;
    }
Update value of the given object or create a new instance if {@code ref} is
null.

@param ref   object to update, could be null
@param bytes bytes
@return same object as {@code ref} or a new instance if it's null
clickhouse-data/src/main/java/com/clickhouse/data/value/ClickHouseStringValue.java