HTTP Request is adding unnecessary header to the POST Rest Call

I am uploading an XML file from local disk via rest call. It is upload the XML file to the server but adding header and footer to the file. Which causing a problem as it is not in the correct format.

Header Value is: -------------------------------28947758029299
Content-Disposition: form-data; name=“in_Attachment”; filename=“11092019021124.xml”
Content-Type: application/octet-stream