Parses @headers and @body to form a new #SoupMultipart
the headers of the HTTP message to parse
the body of the HTTP message to parse
a new #SoupMultipart (or %NULL if the message couldn't be parsed or wasn't multipart).
ConstructionException GTK+ fails to create the object.
2.26
See Implementation
Parses @headers and @body to form a new #SoupMultipart