code: protected List<WorkUnit> getPreviousWorkUnitsForRetry(SourceState state) {
      List<WorkUnit> workUnits = Lists.newArrayList();
      for (WorkUnitState workUnitState : getPreviousWorkUnitStatesForRetry(state)) {
        // Make a copy here as getWorkUnit() below returns an ImmutableWorkUnit
        workUnits.add(WorkUnit.copyOf(workUnitState.getWorkunit()));
      }
  
      return workUnits;
    }
docs: Get a list of previous {@link WorkUnit}s subject for retries.
  
  <p>
  This method uses {@link AbstractSource#getPreviousWorkUnitStatesForRetry(SourceState)}.
  </p>
  
  @param state Source state
  @return list of previous {@link WorkUnit}s subject for retries