scope ping_v3.

static ThreadLocal<PingSource> #forThread = new ThreadLocal<PingSource>() {
  public PingSource initialValue() {
    ret ping_v3_pingSourceMaker()!; 
  }
};

// always returns true for convenience
sbool ping_v3() {
  var source = forThread!;
  callF(source?.action);
  true;
}