private com.google.protobuf.MapField<java.lang.String, java.lang.String>
        internalGetMutableMetadata() {
      if (metadata_ == null) {
        metadata_ =
            com.google.protobuf.MapField.newMapField(MetadataDefaultEntryHolder.defaultEntry);
      }
      if (!metadata_.isMutable()) {
        metadata_ = metadata_.copy();
      }
      bitField0_ |= 0x00008000;
      onChanged();
      return metadata_;
    }
<pre>
Resource labels to represent user-provided metadata.
</pre>

<code>map&lt;string, string&gt; labels = 24;</code>
java-tpu/proto-google-cloud-tpu-v2/src/main/java/com/google/cloud/tpu/v2/Node.java