mongoclient() to MongoDB\Driver\Manager()

hello, i have an application that i would like to upgrade to php 7.0. this application has mongodb as database connection but the connection i had was with mongoclient.

   $di->set("mongo",function () {
           $mongo = new MongoClient( "mongodb://localhost" );
           return $mongo->selectDB("invoicing");
      }, true );

now i would like to use the new mongo driver:

$di->set("mongo",function () {
       $manager = new MongoDB\Driver\Manager("mongodb://localhost:27017"); 
       //somehow selectDB('invoicing') ?
       //to be compatible with the rest of the framework
 }, true );

ps: this works, tested with simple script

$manager = new MongoDB\Driver\Manager("mongodb://localhost:27017"); 
$bulk = new MongoDB\Driver\BulkWrite;
$bulk->insert(['x' => 1]);
$bulk->insert(['x' => 2]);
$bulk->insert(['x' => 3]);
$manager->executeBulkWrite('db.invoicing', $bulk);

$filter = ['x' => ['$gt' => 1]];
$options = [
    'projection' => ['_id' => 0],
    'sort' => ['x' => -1],
];

$query = new MongoDB\Driver\Query($filter, $options);
$cursor = $manager->executeQuery('db.invoicing', $query);

foreach ($cursor as $document) {
    var_dump($document);
}

mongodb version 1.1.8

PHP 7.0.11 (cli)

MongoDB shell version: 2.6.10

Tank you, David Correia