在mule4中查找多部分/表单数据文件的大小

<http:listener-config name="HTTP_Listener_Configuration" doc:name="HTTP Listener Configuration" doc:id="b3f6512e-0228-4f7a-9ae6-2e77d7a356ab" >
    <http:listener-connection host="0.0.0.0" port="8081" />
</http:listener-config>

<flow name="fileSizeFlow" doc:id="7a3bf0a2-c150-4d1b-a4d6-7c2ad0d30873">
    <http:listener doc:name="Listener" doc:id="433df708-756c-4d6c-babe-01aa15c09c17" config-ref="HTTP_Listener_Configuration" path="/upload" />
    <http:request method="POST" doc:name="Request" doc:id="b23a6480-22ad-4123-93a1-1113707158c3" config-ref="HTTP_Request_Configuration">
        <http:body >
            <http:multipart-body >
                <http:part content-type="text/plain" content="payload" />
                <http:part content-type="application/octet-stream" fileName="#[vars.filename]" />
            </http:multipart-body>
        </http:body>
    </http:request>
    <set-variable value="#[vars.filename]" doc:name="File Name" doc:id="d3e21534-f0ff-419d-9a2a-11c9ce59e065" />
    <scripting:execute componentId="fileSizeScript" doc:name="File Size Script" doc:id="da04e4ab-698d-4e2b-b226-0af18c2fd4d0">
        <scripting:script engine="groovy">
            <scripting:text><![CDATA[
                File file = new File(vars.filename);
                return file.length();
            ]]></scripting:text>
        </scripting:script>
    </scripting:execute>
    <logger level="INFO" doc:name="Logger" doc:id="b41a1a29-f28c-4d64-9be8-d8f7ff862ede" message="#[vars.filename] Size: #[payload] bytes" />
</flow>