MongoDB\Database::getReadConcern()

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

object(MongoDB\Driver\ReadConcern)#5 (1) {
  ["level"]=>
  string(8) "majority"
}