private com.google.protobuf.SingleFieldBuilderV3<
            com.google.cloud.tpu.v2alpha1.Reservation.Standard,
            com.google.cloud.tpu.v2alpha1.Reservation.Standard.Builder,
            com.google.cloud.tpu.v2alpha1.Reservation.StandardOrBuilder>
        getStandardFieldBuilder() {
      if (standardBuilder_ == null) {
        if (!(kindCase_ == 2)) {
          kind_ = com.google.cloud.tpu.v2alpha1.Reservation.Standard.getDefaultInstance();
        }
        standardBuilder_ =
            new com.google.protobuf.SingleFieldBuilderV3<
                com.google.cloud.tpu.v2alpha1.Reservation.Standard,
                com.google.cloud.tpu.v2alpha1.Reservation.Standard.Builder,
                com.google.cloud.tpu.v2alpha1.Reservation.StandardOrBuilder>(
                (com.google.cloud.tpu.v2alpha1.Reservation.Standard) kind_,
                getParentForChildren(),
                isClean());
        kind_ = null;
      }
      kindCase_ = 2;
      onChanged();
      return standardBuilder_;
    }
<pre>
A standard reservation.
</pre>

<code>.google.cloud.tpu.v2alpha1.Reservation.Standard standard = 2;</code>
java-tpu/proto-google-cloud-tpu-v2alpha1/src/main/java/com/google/cloud/tpu/v2alpha1/Reservation.java