Pin an item, exempting it from the history's size and memory caps, or let it go again
| this |
a Client instance |
| uuid |
the uuid of the item to pin, or to let go of |
| favourite |
whether the item should be pinned |
| 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 |