Diagnostic feedback when disassembly fails is needed

After a lot of blindly stumbling around in the dark I got DisassemblyDiagnoser to work for a benchmark I'm iterating on, and then a random change to the code being measured made it suddenly stop disassembling all my benchmarks. The only information or diagnostic output I get is:

```
No benchmarks were disassembled
```

It would be awesome if there was some way to get diagnostic information here. Like did decoding the pdb fail? Did nothing get jitted during benchmark execution? etc.