code: @SuppressWarnings(UNUSED)
      @CheckForNull
      @Exported
      public Run getFirstBuild() {
          Run retVal = null;
          for (Job job : getAllJobs()) {
              Run run = job.getFirstBuild();
              if (run != null && (retVal == null || run.getTimestamp().before(retVal.getTimestamp()))) {
                  retVal = run;
              }
          }
          return retVal;
      }
docs: Returns the oldest build in the record.
  
  @return the build or null