private com.google.protobuf.SingleFieldBuilderV3<
            com.google.cloud.tpu.v2alpha1.QueuedResource.Tpu,
            com.google.cloud.tpu.v2alpha1.QueuedResource.Tpu.Builder,
            com.google.cloud.tpu.v2alpha1.QueuedResource.TpuOrBuilder>
        getTpuFieldBuilder() {
      if (tpuBuilder_ == null) {
        if (!(resourceCase_ == 2)) {
          resource_ = com.google.cloud.tpu.v2alpha1.QueuedResource.Tpu.getDefaultInstance();
        }
        tpuBuilder_ =
            new com.google.protobuf.SingleFieldBuilderV3<
                com.google.cloud.tpu.v2alpha1.QueuedResource.Tpu,
                com.google.cloud.tpu.v2alpha1.QueuedResource.Tpu.Builder,
                com.google.cloud.tpu.v2alpha1.QueuedResource.TpuOrBuilder>(
                (com.google.cloud.tpu.v2alpha1.QueuedResource.Tpu) resource_,
                getParentForChildren(),
                isClean());
        resource_ = null;
      }
      resourceCase_ = 2;
      onChanged();
      return tpuBuilder_;
    }
<pre>
Defines a TPU resource.
</pre>

<code>.google.cloud.tpu.v2alpha1.QueuedResource.Tpu tpu = 2;</code>
java-tpu/proto-google-cloud-tpu-v2alpha1/src/main/java/com/google/cloud/tpu/v2alpha1/QueuedResource.java