How do I write out from a roslyn analyzer

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C#

.NET

VS2015

I need to write some output from a Roslyn Analyser. There are two issues here, firstly the additional files example I am following is returning 0 as the number of additional files.

Assuming the load issue gets solved, I can write an entry for every violation but I would prefer to just write the total at the end, but I cannot find any info on line for writing a final status by namespace and class from an analyzer when it is done with a .cs

What I have tried:

I have been following this: article, but I am not getting file in.

The second part, a single summary by namespace and class as opposed to line by line is a very nice to have but I can work without it.

Update
The reason AdditionalFiles failed to perform was because I expected file to be placed in the project folder of the analyzer, but it must be placed in the project folder of the analyzee. I will leave the question open because I would welcome suggestions still on how I might open it at solution level.