Performance issues with metadatas

[dmitryuk]

Closes DamienHarper/auditor-bundle#319
Metadata cache should be configured to start it working

[codecov]

Codecov Report

Merging #137 (d2da374) into 2.x (098fe50) will decrease coverage by 0.03%.
The diff coverage is 94.44%.

@@            Coverage Diff             @@
##              2.x     #137      +/-   ##
==========================================
- Coverage   92.98%   92.95%   -0.04%     
==========================================
  Files          44       44              
  Lines        1526     1561      +35     
==========================================
+ Hits         1419     1451      +32     
- Misses        107      110       +3     

Impacted Files	Coverage Δ
src/Provider/Doctrine/DoctrineProvider.php	94.21% <94.11%> (-1.14%)	⬇️
...trine/Auditing/Transaction/TransactionHydrator.php	83.01% <100.00%> (ø)

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[DamienHarper]

Thanks again @dmitryuk! This one was on my roadmap :)
Do you have some sort of before/after benchmark to better understand the gain?

[dmitryuk]

Test example:

    public function testExampleAsd()
    {
        $container = self::getContainer();
        $provider = new DoctrineProvider(new Configuration([]));
        $em = $container->get('doctrine.orm.entity_manager');

        for ($i = 0; $i< 50; $i++) {
            $provider->loadAnnotations($em, []);
        }
    }

Without cache: Time: 00:26.980, Memory: 52.50 MB

With cache: Time: 00:01.702, Memory: 46.50 MB