Emitted to indicate progress of an update installation.
It is undefined exactly how often it is sent, but it will be emitted at least once at the end with a non-zero status. For
each successful operation in the update, we're also guaranteed to send exactly one signal with progress 100.
| n_ops |
the number of operations that the update consists of |
| op |
the position of the currently active operation |
| progress |
the progress of the currently active operation, as a number between 0 and 100 |
| status |
the overall status of the update |
| error |
the error name if the status is 'failed' |
| error_message |
the error message if the status is 'failed' |