private com.google.protobuf.SingleFieldBuilderV3<
            com.google.cloud.tpu.v2alpha1.QueuedResource.Spot,
            com.google.cloud.tpu.v2alpha1.QueuedResource.Spot.Builder,
            com.google.cloud.tpu.v2alpha1.QueuedResource.SpotOrBuilder>
        getSpotFieldBuilder() {
      if (spotBuilder_ == null) {
        if (!(tierCase_ == 9)) {
          tier_ = com.google.cloud.tpu.v2alpha1.QueuedResource.Spot.getDefaultInstance();
        }
        spotBuilder_ =
            new com.google.protobuf.SingleFieldBuilderV3<
                com.google.cloud.tpu.v2alpha1.QueuedResource.Spot,
                com.google.cloud.tpu.v2alpha1.QueuedResource.Spot.Builder,
                com.google.cloud.tpu.v2alpha1.QueuedResource.SpotOrBuilder>(
                (com.google.cloud.tpu.v2alpha1.QueuedResource.Spot) tier_,
                getParentForChildren(),
                isClean());
        tier_ = null;
      }
      tierCase_ = 9;
      onChanged();
      return spotBuilder_;
    }
<pre>
Optional. The Spot tier.
</pre>

<code>
.google.cloud.tpu.v2alpha1.QueuedResource.Spot spot = 9 [(.google.api.field_behavior) = OPTIONAL];
</code>
java-tpu/proto-google-cloud-tpu-v2alpha1/src/main/java/com/google/cloud/tpu/v2alpha1/QueuedResource.java