code: @Override
      public DERObject toASN1Object()
      {
          ASN1EncodableVector v = new ASN1EncodableVector();
  
          if (cA != null)
          {
              v.add(cA);
  
              if (pathLenConstraint != null)
              {
                  v.add(pathLenConstraint);
              }
          }
  
          return new DERSequence(v);
      }
docs: Produce an object suitable for an ASN1OutputStream.
  <pre>
  BasicConstraints := SEQUENCE {
  cA BOOLEAN DEFAULT FALSE,
  pathLenConstraint INTEGER (0..MAX) OPTIONAL
  }
  </pre>