project_start/phpstorm-stubs/rdkafka/RdKafka/Metadata/Topic.php

<?php

namespace RdKafka\Metadata;

class Topic
{
    /**
     * @return string
     */
    public function getTopic() {}

    /**
     * @return Partition[]
     */
    public function getPartitions() {}

    /**
     * @return mixed
     */
    public function getErr() {}
}