// Create a HostContext for running TFRT functions. Concurrent work queue acts
  // similar to the Tensorflow `inter-op` thread pool, so we'll match the size.
  host_context_ = num_threads ? CreateMultiThreadedHostContext(num_threads)
                              : CreateSingleThreadedHostContext();
  tfrt::RegisterStaticKernels(host_context_->GetMutableRegistry());

  // Build an ExecutionContext from the HostContext.