Adapt dotnet memory allocations

[ricardoboss]

Fixes #699

Adds handling for the memory key in BenchmarkDotNet, in case C# benchmarks are run with the [MemoryDiagnoser] attribute.
If found, adds a new metric allocated measured in bytes.

[epompeii]

@ricardoboss thank you for all of your work so far!
I've made a few suggestions and had a couple of questions.

[epompeii]

Would it be possible to get a smaller example file or are they all this large?

[ricardoboss]

Yeah of course, it was just easily accessible for me. I can provide a smaller one

[epompeii]

We shouldn't need to create a new Latency Measure, we should just use the existing one.

[ricardoboss]

Oh ok, I thought every adapter should define its own set. Will switch to the default measure then

[epompeii]

For consistency, lets move this method above new_iai. Adapters are (mostly) sorted alphabetically across the code base.

[epompeii]

Can the harness collect both memory and wall-clock time measurements at the same time or are they mutually exclusive?

[ricardoboss]

That is above my paygrade... I have no idea 😅

[epompeii]

It seems like it does:

Yes, BenchmarkDotNet collects both simultaneously (well, technically in separate runs to avoid interference, but in the same invocation). When you add [MemoryDiagnoser], the harness:

1. Runs timing measurements normally
2. Performs a separate run for memory/GC metrics (so they don't skew latency numbers)
3. Combines everything into one unified JSON output per benchmark

In the sample file, there are both:

{                                                                                                                                                                                                                                                                                        
    "Method": "Tokenize",                                                                                                                                                                                                                                                                  
    "Parameters": "ExampleFileName=expressions.step",                                                                                                                                                                                                                                      
    "Statistics": {                                                                                                                                                                                                                                                                        
      "Mean": 106.338...,                                                                                                                                                                                                                                                                  
      "Median": 105.607...,
      "StandardDeviation": 3.223...,
      ...
    },
    "Memory": {
      "Gen0Collections": 168,
      "Gen1Collections": 0,
      "Gen2Collections": 0,
      "TotalOperations": 4194304,
      "BytesAllocatedPerOperation": 672
    }
  }

With that being the case, we're going to want to make sure we:

1. Always collect the wall-clock time measurements
2. Optionally collect the memory measurements (if they are present)

Right now, it seems like we are only collecting the memory measurements if they are present (skipping 1.).

[ricardoboss]

I'm not sure I follow... How is the statistics object relevant for the memory allocations? Isn't this used for the latency measurement? That part should mostly be untouched by my changes (latency is still being collected)

[epompeii]

Great! Then we just need to make sure we are testing that the latency measures are still being collected properly.

That is, this adapter_c_sharp_dot_net_memory test should assert on each expected measure (including Latency).

[ricardoboss]

Sure, no problem

[epompeii]

For consistency, lets move this below json and above iai.

[epompeii]

Never unwrap in production code. Try this instead:

Suggested change

	let m = memory.unwrap();
	if let Some(memory) = memory {

Note this would replace the if memory.is_some() { above, so we wouldn't need the let m = memory.unwrap(); at all.