private void ensureSymptomsIsMutable() {
      if (!((bitField0_ & 0x00040000) != 0)) {
        symptoms_ = new java.util.ArrayList<com.google.cloud.tpu.v1.Symptom>(symptoms_);
        bitField0_ |= 0x00040000;
      }
    }
<pre>
Output only. The API version that created this Node.
</pre>

<code>
.google.cloud.tpu.v1.Node.ApiVersion api_version = 38 [(.google.api.field_behavior) = OUTPUT_ONLY];
</code>

@return This builder for chaining.
java-tpu/proto-google-cloud-tpu-v1/src/main/java/com/google/cloud/tpu/v1/Node.java