MongoDB\GridFS\Bucket::getReadConcern()

<?php
$database = (new MongoDB\Client)->getDatabase('test');
$bucket = $database->selectGridFSBucket([
   'readConcern' => new MongoDB\Driver\ReadConcern('majority'),
]);
var_dump($bucket->getReadConcern());

object(MongoDB\Driver\ReadConcern)#3 (1) {
  ["level"]=>
  string(8) "majority"
}