* generated.
     */
    fun keyPair(keyPair: KeyPair) =
      apply {
        this.keyPair = keyPair
      }

    /**
     * Sets the public/private key pair used for this certificate. If unset a key pair will be
     * generated.
     */
    fun keyPair(
      publicKey: PublicKey,
      privateKey: PrivateKey,
    ) = apply {
      keyPair(KeyPair(publicKey, privateKey))
    }

    /**

        .commonName("pinned intermediate")
        .signedBy(pinnedRoot)
        .build()
    val attackerSwitch =
      HeldCertificate
        .Builder()
        .serialNumber(5L)
        .keyPair(attackerIntermediate.keyPair) // share keys between compromised CA and leaf!
        .commonName("attacker")
        .addSubjectAlternativeName("attacker.com")
        .signedBy(pinnedIntermediate)
        .build()

    val keyPair: KeyPair = heldCertificate.keyPair
    val certificatePem: String = heldCertificate.certificatePem()
    val privateKeyPkcs8Pem: String = heldCertificate.privateKeyPkcs8Pem()
    val privateKeyPkcs1Pem: String = heldCertificate.privateKeyPkcs1Pem()
  }

  @Test
  fun heldCertificateBuilder() {
    val keyPair: KeyPair = KeyPairGenerator.getInstance("").genKeyPair()

        .addTrustedCertificate(root.certificate) // BouncyCastle requires at least one
        .heldCertificate(certificate, intermediate.certificate)
        .build()
    assertPrivateKeysEquals(
      certificate.keyPair.private,
      handshakeCertificates.keyManager.getPrivateKey("private"),
    )
    assertThat(handshakeCertificates.keyManager.getCertificateChain("private").toList())