code: @Override
      public void sourceDisconnected(VehicleDataSource source) {
          if(mOperator != null) {
              if(!isActive(source)) {
                  mOperator.onPipelineDeactivated();
                  for(VehicleDataSource s : mSources) {
                      s.onPipelineDeactivated();
                  }
              }
          }
      }
docs: At least one source is not active - if all sources are inactive, notify
  the operator.