Properties registration

@SubscribeEvent
public void onPlayerConstructed(EntityEvent.EntityConstructing event)
{
    if (event.entity instanceof EntityPlayer && !event.entity.worldObj.isRemote)
    {
        EntityPlayer player = (EntityPlayer) event.entity;
        if (player.getExtendedProperties(PlayerProperties.IDENTIFIER) == null)
            player.registerExtendedProperties(PlayerProperties.IDENTIFIER, new PlayerProperties());
    }
}