public void setSound(String sound) {
        this.sound = sound;
    }
<p>
The sound to play when the recipient receives the push notification. You can use the default stream or specify
the file name of a sound resource that's bundled in your app. On an Android platform, the sound file must reside
in /res/raw/.
</p>

@param sound
       The sound to play when the recipient receives the push notification. You can use the default stream or
       specify the file name of a sound resource that's bundled in your app. On an Android platform, the sound
       file must reside in /res/raw/.
aws-java-sdk-pinpoint/src/main/java/com/amazonaws/services/pinpoint/model/GCMMessage.java