public Builder mergeGcePd(
          com.google.cloud.workstations.v1beta.WorkstationConfig.PersistentDirectory
                  .GceRegionalPersistentDisk
              value) {
        if (gcePdBuilder_ == null) {
          if (directoryTypeCase_ == 2
              && directoryType_
                  != com.google.cloud.workstations.v1beta.WorkstationConfig.PersistentDirectory
                      .GceRegionalPersistentDisk.getDefaultInstance()) {
            directoryType_ =
                com.google.cloud.workstations.v1beta.WorkstationConfig.PersistentDirectory
                    .GceRegionalPersistentDisk.newBuilder(
                        (com.google.cloud.workstations.v1beta.WorkstationConfig.PersistentDirectory
                                .GceRegionalPersistentDisk)
                            directoryType_)
                    .mergeFrom(value)
                    .buildPartial();
          } else {
            directoryType_ = value;
          }
          onChanged();
        } else {
          if (directoryTypeCase_ == 2) {
            gcePdBuilder_.mergeFrom(value);
          } else {
            gcePdBuilder_.setMessage(value);
          }
        }
        directoryTypeCase_ = 2;
        return this;
      }
<pre>
A PersistentDirectory backed by a Compute Engine persistent disk.
</pre>

<code>
.google.cloud.workstations.v1beta.WorkstationConfig.PersistentDirectory.GceRegionalPersistentDisk gce_pd = 2;
</code>
java-workstations/proto-google-cloud-workstations-v1beta/src/main/java/com/google/cloud/workstations/v1beta/WorkstationConfig.java