  explicit CollectiveGatherV2OpKernel(OpKernelConstruction* c)
      : CollectiveOpV2Kernel(c) {
    name_ = strings::StrCat(c->def().name(), ": GatherV2");
    VLOG(2) << "CollectiveGatherV2 " << this << " name " << name_
            << " communication_hint " << communication_hint_;
  }
  explicit CollectiveGatherV2OpKernel(OpKernelConstruction* c)
      : CollectiveOpV2Kernel(c) {
    name_ = strings::StrCat(c->def().name(), ": GatherV2");
    VLOG(2) << "CollectiveGatherV2 " << this << " name " << name_
            << " communication_hint " << communication_hint_;
  }