code: synchronized static void initialize(Context context, int goIntent, boolean isAutonomous, ProximityMiddleware.Factory factory) {
          if (singleton == null) {
              singleton = new SPF(context, goIntent, isAutonomous, factory);
          }
      }
docs: Initializes SPF with a {@link Context} reference. Called by
  {@link SPFContext#initialize(int, Context, ProximityMiddleware.Factory)}.
  
  @param context - the context that will be used by SPF