Obtains a [class@Gio.
InputStream] for the next request.
See [[email protected]_part] for details on the workflow.
| this |
the MultipartInputStream. |
| io_priority |
the I/O priority for the request. |
| cancellable |
a Cancellable. |
| callback |
callback to call when request is satisfied. |
| data |
data for |