nextPart
fun nextPart(cancellable: <Error class: unknown class>? = null): <Error class: unknown class><<Error class: unknown class>?>
Obtains an input stream for the next part.
When dealing with a multipart response the input stream needs to be wrapped in a #SoupMultipartInputStream and this function or its async counterpart need to be called to obtain the first part for reading.
After calling this function, method@MultipartInputStream.get_headers can be used to obtain the headers for the first part. A read of 0 bytes indicates the end of the part; a new call to this function should be done at that point, to obtain the next part.
Return
a new #GInputStream, or null if there are no more parts
Parameters
cancellable
a #GCancellable