dotnet format analyzers extremely slow when trying to apply to solution

I'm trying to apply a `dotnet format analyzers` fix for NUnit.Analyzers.

Right now I'm trying to apply just a single diagnostic ( NUnit2005 ).

When I try to apply a fix to the solution, it quickly consumes all my memory and takes a very long time. It's currently at **3 hours** of CPU time and counting. I'll report back when I know how long it takes in the end.

I feel like if I were to write a loop to apply the change project-by-project or even file-by-file then it'd have finished by now.

There's something very odd with how much longer it takes to apply a fix to the whole solution compared to applying the fix file-by-file.

There are only ~1500 failures reported as affected by NUnit2005 when I build.

Solution is ~250 projects. I'm not sure how many SLOC.