terminal.integrated.env.windows for Integrated Terminal

I'm trying to set variable before start the Integrated Terminal

User Setting:

{
    "terminal.integrated.env.windows": {
        "foo": "bar"
    }
}

Then View > Integrated Terminal

Windows PowerShell
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PS C:\bar> echo $foo
PS C:\bar> 

It's seem not work, It's bug or I'm wrong?

VSCode Version: 1.16.1

PS: Already seem Set global $PATH environment variable in VS Code