I share the mongodb connection thought all http requests that my webserver (nodejs) receives.

When i want to stop the webserver, before all, I refuse new connections, close mongodb connection, and the process exits graceful (all sockets are closed and the event loop is empty).

But, if the `MongoClient.close` method is called while a http request writes/reads from datas from mongo, an exception is thrown.

As attachment, there's an example of this problem.

How can I wait for all connection closing?