Add extra statistics column for part of a function or another internal function

Question

I have the following Benchmark code:

public class BenchMarkDemo
{
    [Benchmark] 
    public void Foo1() 
    { 
        /* ... */ 
        var stream = dosomethingElse();
        var output = Bar1(stream);
        /* ... */ 
    }

    public string Bar1(Stream stream) { 
        return streamToString(stream);
    }
}

When I run benchmark I get columns like Mean, StdDev for Foo1 function. But I also want to add more columns (statistics) to the same row that has Bar1 mean and Bar1 StdDev.

How can I achieve that?