title: Type Error "string" must be a string, Buffer, or ArrayBuffer
body: <p>I am in Node trying to send a http call to an endpoint. I'm not getting any response, and im certain I have set something up incorrectly. My request worked on postman. Any help woud be awesome!</p>
  
  <pre class="lang-js prettyprint-override"><code>var XMLHttpRequest = require("xmlhttprequest").XMLHttpRequest;
  
  curlUpdate = function curlUpdate() {
      var xhr = new XMLHttpRequest();
      xhr.open("POST", "www.example.com", false);
      xhr.setRequestHeader('Content-Type', 'application/json');
      xhr.send({
          FirstName: "john",
          LastName: "doe",
          MerchantSessionID: "817281271",
          DateOfBirth: "12,24,1985",
          ProductTypeID: "xxxxxxxxx"
      });
      console.log(xhr.responseText);
  };
  </code></pre>