358.4.2. usage 示例：将 map 整合到固定宽度格式中

<route>
    <from uri="direct:input"/>
    <marshal>
        <univocity-fixed padding="_">
            <univocity-header length="5"/>
            <univocity-header length="5"/>
            <univocity-header length="5"/>
        </univocity-fixed>
    </marshal>
    <to uri="mock:result"/>
</route>