使用url的datatask工作正常，而使用request调用datatask则返回带有垃圾的数据

I am invoking a webservice using URLSession.shared.dataTask. Invoking it with, datatask with url works fine whereas calling datatask with request returns data with "garbage at the end". Can someone explain me why? Following is the function in 2 formats.I am invoking a webservice using URLSession.sha