apply {
        this.commonName = cn
      }

    /** Sets the certificate's organizational unit (OU). If unset this field will be omitted. */
    fun organizationalUnit(ou: String) =
      apply {
        this.organizationalUnit = ou
      }

    /** Sets this certificate's serial number. If unset the serial number will be 1. */
    fun serialNumber(serialNumber: BigInteger) =
      apply {

    builder = builder.validityInterval(0L, 0L)
    builder = builder.duration(0L, TimeUnit.SECONDS)
    builder = builder.addSubjectAlternativeName("")
    builder = builder.commonName("")
    builder = builder.organizationalUnit("")
    builder = builder.serialNumber(BigInteger.ZERO)
    builder = builder.serialNumber(0L)
    builder = builder.keyPair(keyPair)
    builder = builder.keyPair(keyPair.public, keyPair.private)