private com.google.protobuf.SingleFieldBuilderV3<
            com.google.cloud.vmmigration.v1.MigratingVm,
            com.google.cloud.vmmigration.v1.MigratingVm.Builder,
            com.google.cloud.vmmigration.v1.MigratingVmOrBuilder>
        getMigratingVmFieldBuilder() {
      if (migratingVmBuilder_ == null) {
        migratingVmBuilder_ =
            new com.google.protobuf.SingleFieldBuilderV3<
                com.google.cloud.vmmigration.v1.MigratingVm,
                com.google.cloud.vmmigration.v1.MigratingVm.Builder,
                com.google.cloud.vmmigration.v1.MigratingVmOrBuilder>(
                getMigratingVm(), getParentForChildren(), isClean());
        migratingVm_ = null;
      }
      return migratingVmBuilder_;
    }
<pre>
Required. The update request body.
</pre>

<code>
.google.cloud.vmmigration.v1.MigratingVm migrating_vm = 2 [(.google.api.field_behavior) = REQUIRED];
</code>
java-vmmigration/proto-google-cloud-vmmigration-v1/src/main/java/com/google/cloud/vmmigration/v1/UpdateMigratingVmRequest.java