public Builder setPreparingVmDisks(
        com.google.cloud.vmmigration.v1.PreparingVMDisksStep.Builder builderForValue) {
      if (preparingVmDisksBuilder_ == null) {
        step_ = builderForValue.build();
        onChanged();
      } else {
        preparingVmDisksBuilder_.setMessage(builderForValue.build());
      }
      stepCase_ = 6;
      return this;
    }
<pre>
Preparing VM disks step.
</pre>

<code>.google.cloud.vmmigration.v1.PreparingVMDisksStep preparing_vm_disks = 6;</code>
java-vmmigration/proto-google-cloud-vmmigration-v1/src/main/java/com/google/cloud/vmmigration/v1/CutoverStep.java