Upload an item to a pastebin service, and answer where it landed.
The reply comes when the upload has finished, and an upload that failed fails the call. An empty uuid uploads the current
item.
| this |
a Client instance |
| uuid |
the uuid of the element we want to upload |
| cancellable |
a Cancellable to abandon the call with |
| callback |
a TaskReadyCallback to call once the request is satisfied, or null to ignore the result |
| user_data |
the data to pass to |