code: public LoadStatisticsSnapshot computeSnapshot() {
          if (modern) {
              return computeSnapshot(Jenkins.getInstance().getQueue().getBuildableItems());
          } else {
              int t = computeTotalExecutors();
              int i = computeIdleExecutors();
              return new LoadStatisticsSnapshot(t, t, Math.max(i-t,0), Math.max(t-i,0), i, i, computeQueueLength());
          }
      }
docs: Computes a self-consistent snapshot of the load statistics.
  
  Note: The original method of computing load statistics would compute the total and idle counts independently
  which could lead to counting errors while jobs started in between the different state counting operations.
  By returning a {@link LoadStatisticsSnapshot} we get a single consistent view of the counts which was valid
  for at least one point in time during the execution of this method.
  
  @return a self-consistent snapshot of the load statistics.
  @since 1.607