Make sure a Monolog logger can log

monolog-setup.php

<?php

$handler = new RotatingFileHandler(ABSPATH . '../logs/log.log', 0, Logger::DEBUG, true, 0777);

try {
    $record = array(
        'message' => (string) "Write test",
        'context' => null,
        'level' => Logger::DEBUG,
        'level_name' => 'DEBUG',
        'channel' => 'online-topups',
        'datetime' => \DateTime::createFromFormat('U.u', sprintf('%.6F', microtime(true)), new DateTimeZone('UTC'))->setTimezone(new DateTimeZone('UTC')),
        'extra' => array(),
    );
    $handler->handle($record);
} catch (UnexpectedValueException $e) {
    error_log('switching logger');
    $handler = new \Monolog\Handler\NullHandler;
}