docs: public WebSocketExtension setParameter(String key, String value)
      {
          // Check the validity of the key.
          if (Token.isValid(key) == false)
          {
              // The key is not a valid token.
              throw new IllegalArgumentException("'key' is not a valid token.");
          }
  
          // If the value is not null.
          if (value != null)
          {
              // Check the validity of the value.
              if (Token.isValid(value) == false)
              {
                  // The value is not a valid token.
                  throw new IllegalArgumentException("'value' is not a valid token.");
              }
          }
  
          mParameters.put(key, value);
  
          return this;
      }