title: Difference between bulk.ToString() and bulk.tojson()
body: <p>Is there any difference between <a href="https://docs.mongodb.org/v3.0/reference/method/Bulk.toString/" rel="nofollow">bulk.ToString()</a> and <a href="https://docs.mongodb.org/manual/reference/method/Bulk.tojson/" rel="nofollow">bulk.tojson()</a> in the mongodb?</p>