message: [tf.data / Bigtable] Use builder pattern for client options
diff: @@ -76,8 +76,10 @@ class BigtableClientOp : public OpKernel {
  cinfo_.container(), cinfo_.name(), &resource,
  [this, ctx](
  BigtableClientResource** ret) EXCLUSIVE_LOCKS_REQUIRED(mu_) {
  - auto client_options = google::cloud::bigtable::ClientOptions();
  - client_options.set_connection_pool_size(connection_pool_size_);
  + auto client_options =
  + google::cloud::bigtable::ClientOptions()
  + .set_connection_pool_size(connection_pool_size_)
  + .set_data_endpoint("batch-bigtable.googleapis.com");
  auto channel_args = client_options.channel_arguments();
  channel_args.SetMaxReceiveMessageSize(
  max_receive_message_size_);
  