Is there a way to get an Android user email address through Unity?

Based on this reference, Java seems to be able to obtain it from the account manager.
How do I do the same with Unity?

http://y-anz-m.blogspot.jp/2010/09/android_23.html

If you try the Google official plug-in,
I can get the account name and unique ID, but
I can't see your email address.(Or I don't know how to do it)

playgameservices/play-games-plugin-for-unity·GitHub
https://github.com/playgameservices/play-games-plugin-for-unity

The email address will be used to determine the distribution of special items to kickstarter supporters.
I wish I could identify the supporter's account from Unity.

↓↓
I want to access classes with enhanced Android (Java) Activity from Unity (C#)

Now that we have resolved this issue, Unity has also accessed the account manager I wrote in java to obtain an email address.I think it can be used as one of the decisions.