@java.lang.Override
        public final boolean isInitialized() {
          byte isInitialized = memoizedIsInitialized;
          if (isInitialized == 1) return true;
          if (isInitialized == 0) return false;

          memoizedIsInitialized = 1;
          return true;
        }
<pre>
Optional. Prefix of node_ids in case of multislice request.
Should follow the `^[A-Za-z0-9_.~+%-]+$` regex format.
If node_count = 3 and node_id_prefix = "np", node ids of nodes
created will be "np-0", "np-1", "np-2". If this field is not
provided we use queued_resource_id as the node_id_prefix.
</pre>

<code>string node_id_prefix = 2 [(.google.api.field_behavior) = OPTIONAL];</code>

@return The bytes for nodeIdPrefix.
java-tpu/proto-google-cloud-tpu-v2/src/main/java/com/google/cloud/tpu/v2/QueuedResource.java