谷歌驱动iOS SDK:获取用户可用空间

I am building an app that uses the Google Drive iOS SDK to upload files to a user's Google Drive account. Due to the size of files that are being uploaded, I would like to know how much space the user is using and has available. For example I plan to have a label in my app that shows the user is using 10gb/100gb currently.I am building an app that uses the Google Drive