docs: private OCSPReq createRequest(
        SFPair<Certificate, Certificate> pairIssuerSubject)
    {
      Certificate issuer = pairIssuerSubject.left;
      Certificate subject = pairIssuerSubject.right;
      OCSPReqBuilder gen = new OCSPReqBuilder();
      try
      {
        DigestCalculator digest = new SHA1DigestCalculator();
        X509CertificateHolder certHolder = new X509CertificateHolder(issuer.getEncoded());
        CertificateID certId = new CertificateID(
            digest, certHolder, subject.getSerialNumber().getValue());
        gen.addRequest(certId);
        return gen.build();
      }
      catch (OCSPException | IOException ex)
      {
        throw new RuntimeException("Failed to build a OCSPReq.");
      }
    }