private com.google.protobuf.MapField<java.lang.String, java.lang.String> internalGetMetadata() {
      if (metadata_ == null) {
        return com.google.protobuf.MapField.emptyMapField(MetadataDefaultEntryHolder.defaultEntry);
      }
      return metadata_;
    }
<pre>
Output only. The VM Boot Option, as set in the source vm.
</pre>

<code>
.google.cloud.vmmigration.v1.ComputeEngineBootOption boot_option = 15 [(.google.api.field_behavior) = OUTPUT_ONLY];
</code>

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