private com.google.protobuf.SingleFieldBuilderV3<
            com.google.cloud.tpu.v2.QueuedResource.Guaranteed,
            com.google.cloud.tpu.v2.QueuedResource.Guaranteed.Builder,
            com.google.cloud.tpu.v2.QueuedResource.GuaranteedOrBuilder>
        getGuaranteedFieldBuilder() {
      if (guaranteedBuilder_ == null) {
        if (!(tierCase_ == 4)) {
          tier_ = com.google.cloud.tpu.v2.QueuedResource.Guaranteed.getDefaultInstance();
        }
        guaranteedBuilder_ =
            new com.google.protobuf.SingleFieldBuilderV3<
                com.google.cloud.tpu.v2.QueuedResource.Guaranteed,
                com.google.cloud.tpu.v2.QueuedResource.Guaranteed.Builder,
                com.google.cloud.tpu.v2.QueuedResource.GuaranteedOrBuilder>(
                (com.google.cloud.tpu.v2.QueuedResource.Guaranteed) tier_,
                getParentForChildren(),
                isClean());
        tier_ = null;
      }
      tierCase_ = 4;
      onChanged();
      return guaranteedBuilder_;
    }
<pre>
Optional. The Guaranteed tier
</pre>

<code>
.google.cloud.tpu.v2.QueuedResource.Guaranteed guaranteed = 4 [(.google.api.field_behavior) = OPTIONAL];
</code>
java-tpu/proto-google-cloud-tpu-v2/src/main/java/com/google/cloud/tpu/v2/QueuedResource.java