}

  @Suppress("DEPRECATION")
  companion object {
    // Most secure but generally supported list.
    private val RESTRICTED_CIPHER_SUITES =
      listOf(
        // TLSv1.3.
        CipherSuite.TLS_AES_128_GCM_SHA256,
        CipherSuite.TLS_AES_256_GCM_SHA384,
        CipherSuite.TLS_CHACHA20_POLY1305_SHA256,
        // TLSv1.0, TLSv1.1, TLSv1.2.
        CipherSuite.TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256,