code: public void marshall(StartGameSessionPlacementRequest startGameSessionPlacementRequest, ProtocolMarshaller protocolMarshaller) {
  
          if (startGameSessionPlacementRequest == null) {
              throw new SdkClientException("Invalid argument passed to marshall(...)");
          }
  
          try {
              protocolMarshaller.marshall(startGameSessionPlacementRequest.getPlacementId(), PLACEMENTID_BINDING);
              protocolMarshaller.marshall(startGameSessionPlacementRequest.getGameSessionQueueName(), GAMESESSIONQUEUENAME_BINDING);
              protocolMarshaller.marshall(startGameSessionPlacementRequest.getGameProperties(), GAMEPROPERTIES_BINDING);
              protocolMarshaller.marshall(startGameSessionPlacementRequest.getMaximumPlayerSessionCount(), MAXIMUMPLAYERSESSIONCOUNT_BINDING);
              protocolMarshaller.marshall(startGameSessionPlacementRequest.getGameSessionName(), GAMESESSIONNAME_BINDING);
              protocolMarshaller.marshall(startGameSessionPlacementRequest.getPlayerLatencies(), PLAYERLATENCIES_BINDING);
              protocolMarshaller.marshall(startGameSessionPlacementRequest.getDesiredPlayerSessions(), DESIREDPLAYERSESSIONS_BINDING);
              protocolMarshaller.marshall(startGameSessionPlacementRequest.getGameSessionData(), GAMESESSIONDATA_BINDING);
          } catch (Exception e) {
              throw new SdkClientException("Unable to marshall request to JSON: " + e.getMessage(), e);
          }
      }
docs: Marshall the given parameter object.