Optional[customOptional[unknownNumber of ticks completed so far. MUST be between 0 and total_tick_count, inclusive. MUST equal total_tick_count if the task or step is finished.
Total number of ticks (work units) to be completed. MUST be greater than 0.
Information about the work done by the task or its step, expressed in ticks (abstract work units). Each tick may represent a real measurement (e.g., VMs created, KiB uploaded), number of substeps or a percentage of work completed.