Why is the MongoDB Node Driver generating instance pool destroyed errors?
<p>When I run the following code I am getting the error message '<strong>MongoError: server instance pool was destroyed</strong>'.  Any idea why or how to fix this?</p>

<pre><code>var csv = require('./importer.js');
var MongoClient = require('mongodb').MongoClient;
var assert = require('assert');
var ObjectId = require('mongodb').ObjectID;
var url = 'mongodb://.....';


MongoClient.connect(url, function(err, db) {

    assert.equal(null, err);
    console.log("Connected correctly to server.");

    csv.foreach('data/airports.csv', function(airport){
        db.collection('airports').insertOne(airport, function(err, result) {
            if(err) {
                console.log(err)
            } else {
                console.log("Inserted: " + airport.ident);
            }
        });
    });

    db.close();
});
</code></pre>