dist/flow.js
function () {
      // Set up request and listen for event
      this.xhr = new XMLHttpRequest();
      this.xhr.addEventListener("load", this.testHandler, false);
      this.xhr.addEventListener("error", this.testHandler, false);
      var testMethod = evalOpts(this.flowObj.opts.testMethod, this.fileObj, this);
      var data = this.prepareXhrRequest(testMethod, true);
      this.xhr.send(data);
    }
function () {
      // Set up request and listen for event
      this.xhr = new XMLHttpRequest();
      this.xhr.addEventListener("load", this.testHandler, false);
      this.xhr.addEventListener("error", this.testHandler, false);
      var testMethod = evalOpts(this.flowObj.opts.testMethod, this.fileObj, this);
      var data = this.prepareXhrRequest(testMethod, true);
      this.xhr.send(data);
    }
Makes a GET request without any data to see if the chunk has already
been uploaded in a previous session
@function