public static Builder newBuilder() {
    return DEFAULT_INSTANCE.toBuilder();
  }
<pre>
API version.
</pre>

<code>string api_version = 7;</code>

@return The bytes for apiVersion.
java-tpu/proto-google-cloud-tpu-v2alpha1/src/main/java/com/google/cloud/tpu/v2alpha1/OperationMetadata.java