Where is the library for HttpClientRequest?

I have the following code:

var jp = {};

jp.flowState = 'ST_PendingPDFupload';

jp.pressedButton = 'S_Submit1';

jp.F_Value1 = this.getField("F_Value1").value.toString();

var UID = this.getField("UID").value.toString();

var urla = 'https://domain/forms-basic/secure/org/data/ba48a093-5a1d-40ef-87f6-bb196b95fa9f/F_NewForm1/';

var urlb = '?freedomIdentifyKey=55';

var url = (urla + UID + urlb);

var http = new HttpClientRequest(url);

http.header["Cookie"] = "freedomIdentifyKey=55";

http.header["Content-Type"] = "application/json; charset=utf-8";

http.header["Accept"] = "application/json; charset=utf-8";

http.body = JSON.stringify(jp);

http.method = "PUT";

http.connect();

http.execute();

http.dispose();

http.disconnect();

I am getting an error in Acrobat of: ReferenceError: HttpClientRequest is not defined.  I believe I need to add something like:

loadLibrary("nms:amcIntegration.js");

But I am not sure what the library is.