code: @Override
      public String toCSV() {
          int nbManagedVMs = -1;
          long core = 0;
          long spe = 0;
          long d = 0;
          int solutions = 0;
          if (!stages.isEmpty()) {
              solutions = stages.get(stages.size() - 1).getSolutions().size();
          }
          boolean completed = true;
          for (SolvingStatistics sol : stages) {
              nbManagedVMs = Math.max(nbManagedVMs, sol.getNbManagedVMs());
              core += sol.getCoreBuildDuration();
              spe += sol.getSpecializationDuration();
              d += sol.getMetrics().timeCount();
              completed &= sol.completed();
              if (sol.getSolutions().isEmpty()) {
                  solutions = 0;
              }
          }
  
          return String.format("%d;%d;%d;%d;%d;%d", nbManagedVMs,
                  core,
                  spe,
                  d,
                  solutions,
                  completed ? 1 : 0);
  
      }
docs: Print the statistics as a CSV line.
  Statistics are computed wrt. the different stages:
  - the maximum number of managed VMs
  - the cumulative getCoreBuildDuration()
  - the cumulative getSpecializationDuration()
  - the cumulative getMetrics().timeCount
  - the number of solutions for the last stage or 0 if any of the stages does not have at least a solution
  - completed ? 1 if all the stages are completed
  
  @return a CSV formatted string