MongoDB\Database::getWriteConcern()

<?php
$database = (new MongoDB\Client)->selectDatabase('test', [
   'writeConcern' => new MongoDB\Driver\WriteConcern(1, 0, true),
]);
var_dump($database->getWriteConcern());

object(MongoDB\Driver\WriteConcern)#5 (2) {
  ["w"]=>
  int(1)
  ["j"]=>
  bool(true)
}