code: public void setParameter(String parameterName, String parameterValue) {
          log.trace("enter PostMethod.setParameter(String, String)");
  
          removeParameter(parameterName);
          addParameter(parameterName, parameterValue);
      }
docs: Sets the value of parameter with parameterName to parameterValue. This method
  does not preserve the initial insertion order.
  
  @param parameterName name of the parameter
  @param parameterValue value of the parameter
  
  @since 2.0