Logging with Zend Framework 2

Code
<?php

use Zend\Log\Logger;
use 
Zend\Log\Writer\Mock;
use 
Zend\Debug\Debug;

$logger = new Logger();

$writer = new Mock();
$logger->addWriter($writer);

$logger->err('An error happened!');
$logger->notice('Did you notice?');
$logger->warn('Danger, Will Robinson!');

// show all added log messages of Mock writer
foreach ($writer->events as $event) {
    
Debug::dump($event);
}
Result
array(5) {
  ["timestamp"] => object(DateTime)#373 (3) {
    ["date"] => string(26) "2017-12-11 22:07:18.555948"
    ["timezone_type"] => int(3)
    ["timezone"] => string(13) "Europe/Berlin"
  }
  ["priority"] => int(3)
  ["priorityName"] => string(3) "ERR"
  ["message"] => string(18) "An error happened!"
  ["extra"] => array(0) {
  }
}
array(5) {
  ["timestamp"] => object(DateTime)#367 (3) {
    ["date"] => string(26) "2017-12-11 22:07:18.562310"
    ["timezone_type"] => int(3)
    ["timezone"] => string(13) "Europe/Berlin"
  }
  ["priority"] => int(5)
  ["priorityName"] => string(6) "NOTICE"
  ["message"] => string(15) "Did you notice?"
  ["extra"] => array(0) {
  }
}
array(5) {
  ["timestamp"] => object(DateTime)#369 (3) {
    ["date"] => string(26) "2017-12-11 22:07:18.562331"
    ["timezone_type"] => int(3)
    ["timezone"] => string(13) "Europe/Berlin"
  }
  ["priority"] => int(4)
  ["priorityName"] => string(4) "WARN"
  ["message"] => string(22) "Danger, Will Robinson!"
  ["extra"] => array(0) {
  }
}
Used Versions
PHP 7.1, Zend 3.0, Symfony 3.2, Laravel 5.2, PHPUnit 5.6, Doctrine 2.6