code: protected String setEscapedParameter(HttpMessage message, String param, String value) {
          return variant.setEscapedParameter(message, originalPair, param, value);
      }
docs: Sets the parameter into the given {@code message}. If both parameter name and value are {@code null}, the parameter will
  be removed.
  <p>
  The value is expected to be properly encoded/escaped.
  
  @param message the message that will be changed
  @param param the name of the parameter
  @param value the value of the parameter
  @return the parameter set
  @see #setParameter(HttpMessage, String, String)