How to resolve SSS_XML_DOM_EXCEPTION when using UTF-16 with n/xml in SuiteScript 2.1

when I'm using the n/xml module to parse XML string, it throws an error when the encoding is UTF - 16. What else can I use besides that XML parser?

Example :

// this works

let xmlString = '<?xml version="1.0" encoding="UTF-8"?><config date="1465467658668" transient="false">Some content</config>';

let xmlDocument = xml.Parser.fromString(xmlString);

// it doesn't work

// it throws SSS_XML_DOM_EXCEPTION, Content is not allowed in prolog. [line 1, column 40]

let xmlString = '<?xml version="1.0" encoding="UTF-16"?><config date="1465467658668" transient="false">Some content</config>';

let xmlDocument = xml.Parser.fromString(xmlString);