How to use the fast-azure-storage.Agent function in fast-azure-storage

let Promise     = require('promise');
let debug       = require('debug')('app:queue');
let assert      = require('assert');
let base32      = require('thirty-two');
let querystring = require('querystring');
let url         = require('url');
let azure       = require('fast-azure-storage');
let crypto      = require('crypto');
let taskcluster = require('taskcluster-client');
let slugid      = require('slugid');

/** Timeout for azure queue requests */
const AZURE_QUEUE_TIMEOUT = 7 * 1000;

/** Azure queue agent used for all instances of the queue client */
let globalAzureQueueAgent = new azure.Agent({
  keepAlive:        true,
  maxSockets:       100,
  maxFreeSockets:   100,
});

/** Decode Url-safe base64, our identifiers satisfies these requirements */
let decodeUrlSafeBase64 = data => {
  return new Buffer(data.replace(/-/g, '+').replace(/_/g, '/'), 'base64');
};

/** Get seconds until `target` relative to now (by default) */
let secondsTo = (target, relativeTo = new Date()) => {
  var delta = Math.floor((target.getTime() - relativeTo.getTime()) / 1000);
  return Math.max(delta, 0); // never return negative time
};