workloadStep method
The step workload is in the frame as (addWorkload): what it was
told, or why it was refused. Null for a workload not added here.
Implementation
WorkloadStep? workloadStep(ComputeWorkload workload) {
for (final step in _store.workloads) {
if (identical(step.workload, workload)) return step;
}
return null;
}