nextPartAsync
fun nextPartAsync(ioPriority: <Error class: unknown class>, cancellable: <Error class: unknown class>? = null, callback: <Error class: unknown class>?)
Obtains a class@Gio.InputStream for the next request.
See method@MultipartInputStream.next_part for details on the workflow.
Parameters
ioPriority
the I/O priority for the request.
cancellable
a #GCancellable.
callback
callback to call when request is satisfied.