extension_attributes.xml

<?xml version="1.0"?>
<!--
/**
 * Copyright © Magento, Inc. All rights reserved.
 * See COPYING.txt for license details.
 */
-->
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:Api/etc/extension_attributes.xsd">
    <extension_attributes for="Magento\AsynchronousOperations\Api\Data\OperationInterface">
        <attribute code="start_time" type="string">
            <resources>
                <resource ref="Magento_Logging::system_magento_logging_bulk_operations"/>
            </resources>
            <join reference_table="magento_bulk" join_on_field="bulk_uuid" reference_field="uuid">
                <field column="start_time">start_time</field>
            </join>
        </attribute>
    </extension_attributes>
</config>