Example for adding a document:
$document = [
'name' => 'John',
'active' => true,
'info' => ['genre' => 'male', 'age' => 30]
];
$bulk = new \MongoDB\Driver\BulkWrite;
$_id1 = $bulk->insert($document);
$result = $manager->executeBulkWrite('database_name.collection_name', $bulk);