Magento 2: I need to run observer function through Cron job

I want to run an observer function through a Cron job. Can anyone share the simple observer function.?

Here is my code

<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:module:Magento_Cron:etc/crontab.xsd">
     <group id="default">
         <job name="abandon_cron_test" instance="AbcAbandonObserverAbandon" method="execute">
               <schedule>* * * * *</schedule>
         </job>
     </group>
</config>

Observer file

Abandon.php

class Abandon implements ObserverInterface
{

    protected $_objectManager;

    /**
    * @param MagentoFrameworkObjectManagerInterface $objectManager
    */
    public function __construct(
        MagentoFrameworkObjectManagerInterface $objectManager
    ) {
        $this->_objectManager = $objectManager;
    }
    public function execute(MagentoFrameworkEventObserver $observer)
    {
        $writer = new ZendLogWriterStream(BP . '/var/log/abondoncronrunobserver.log');
        $logger = new ZendLogLogger();
        $logger->addWriter($writer);
        $logger->info('cron successfully');
    }
}

NO, there is no hard requirement to run the observer in cron. Here am using cron/run.php file to use in cronjob. But am not getting quote data in this file.

Here is my code:

  namespace ABCAbandonCron;

    use PsrLogLoggerInterface;
    class Run {

    protected $logger;
    protected $scopeConfig;
    public function __construct(
    LoggerInterface $logger,
    MagentoFrameworkAppConfigScopeConfigInterface $scopeConfig
    ){
    $this->logger = $logger;
    $this->scopeConfig = $scopeConfig;

    }


    public function execute(){

    $objectManager = MagentoFrameworkAppObjectManager::getInstance();
    $cartObj = $objectManager->get('MagentoCheckoutModelCart'); 
    $quoteId = $cartObj->getQuote()->getId();
    $itemsArray = $cartObj->getQuote()->getAllItems();
    foreach($itemsArray as $item) {
    $productName[] = $item->getName();
    }
    if(is_array($productName)){
    $productNames .= implode(';',$productName);
    }
    $abdata['productNames'] = $productNames;
    $abdata['quoteid'] = $quoteId;
    return $abdata;
    }

    }

Thanks