public void setGameProperties(java.util.Collection<GameProperty> gameProperties) {
        if (gameProperties == null) {
            this.gameProperties = null;
            return;
        }

        this.gameProperties = new java.util.ArrayList<GameProperty>(gameProperties);
    }
<p>
A set of key-value pairs that can store custom data in a game session. For example:
<code>{"Key": "difficulty", "Value": "novice"}</code>.
</p>

@param gameProperties
       A set of key-value pairs that can store custom data in a game session. For example:
       <code>{"Key": "difficulty", "Value": "novice"}</code>.
aws-java-sdk-gamelift/src/main/java/com/amazonaws/services/gamelift/model/StartGameSessionPlacementRequest.java