// Guarded by this.
  private lateinit var publicSuffixListBytes: ByteArray
  private lateinit var publicSuffixExceptionListBytes: ByteArray

  /**
   * Returns the effective top-level domain plus one (eTLD+1) by referencing the public suffix list.
   * Returns null if the domain is a public suffix or a private address.
   *
   * Here are some examples:
   *
   * ```java