private com.google.protobuf.RepeatedFieldBuilderV3<
            com.google.cloud.workstations.v1beta.WorkstationConfig.PersistentDirectory,
            com.google.cloud.workstations.v1beta.WorkstationConfig.PersistentDirectory.Builder,
            com.google.cloud.workstations.v1beta.WorkstationConfig.PersistentDirectoryOrBuilder>
        getPersistentDirectoriesFieldBuilder() {
      if (persistentDirectoriesBuilder_ == null) {
        persistentDirectoriesBuilder_ =
            new com.google.protobuf.RepeatedFieldBuilderV3<
                com.google.cloud.workstations.v1beta.WorkstationConfig.PersistentDirectory,
                com.google.cloud.workstations.v1beta.WorkstationConfig.PersistentDirectory.Builder,
                com.google.cloud.workstations.v1beta.WorkstationConfig
                    .PersistentDirectoryOrBuilder>(
                persistentDirectories_,
                ((bitField0_ & 0x00002000) != 0),
                getParentForChildren(),
                isClean());
        persistentDirectories_ = null;
      }
      return persistentDirectoriesBuilder_;
    }
<pre>
Optional. Directories to persist across workstation sessions.
</pre>

<code>
repeated .google.cloud.workstations.v1beta.WorkstationConfig.PersistentDirectory persistent_directories = 13 [(.google.api.field_behavior) = OPTIONAL];
</code>
java-workstations/proto-google-cloud-workstations-v1beta/src/main/java/com/google/cloud/workstations/v1beta/WorkstationConfig.java