docs: protected int calculatePortTwo(final int portOne) {
          int portTwo = this.portTwo;
  
          if (portTwo <= 0) {
              portTwo = portOne + 1;
          }
  
          if (this.logger.isDebugEnabled()) {
              this.logger.debug("Using " + portTwo + " for portTwo.");
          }
  
          return portTwo;
      }