How can I throttle stack of api requests?
<p>I have an array of ids, and I want to make an api request for each id, but I want to control how many requests are made per second, or better still, have only 5 open connections at any time, and when a connection is complete, fetch the next one.</p>

<p>Currently I have this, which just fires off all the requests at the same time:</p>

<pre><code>_.each([1,2,3,4,5,6,7,8,9,10], function(issueId) {
    github.fetchIssue(repo.namespace, repo.id, issueId, filters)
        .then(function(response) {
            console.log('Writing: ' + issueId);
            writeIssueToDisk(fetchIssueCallback(response));
        });
});
</code></pre>