From mongodb/mongo-php-library#83:

What I have found out, if I execute any method on Collection object within containers closure, this works no problem This is the original code (League Container service provider):

$this->getContainer()->add('mongo-collection', function () {
    $context = stream_context_create(['ssl' => [
        'allow_self_signed' => true,
        'verify_peer'       => false,
        'verify_peer_name'  => false,
        'verify_expiry'     => false]
    ]);

    $manager = new Manager('mongodb://127.0.0.1:27017', ['ssl' => true], ['context' => $context]);

    $collection = new Collection($manager, 'dbName.collectionName');

    return $collection;
});

And if I add:

$collection->count();

right before the return, it works. If I comment it out, I get segfault. I have also tried other methods like findOne() and it again works.