Add allocation details for AspNetCore instrumentation benchmarks

[utpilla]

Towards #4376

Changes

• Added allocation details for AspNetCore instrumentation benchmarks for better performance assessment and identifying scope of improvement

Note: This is for .NET 7.

Analysis

I used the .NET Object Allocation Tracking tool: https://learn.microsoft.com/en-us/visualstudio/profiling/dotnet-alloc-tool?view=vs-2022

I used the following setup to compare the allocations of the different scenarios:

var builder = WebApplication.CreateBuilder();
builder.Logging.ClearProviders();
var app = builder.Build();
app.MapGet("/", async context => await context.Response.WriteAsync($"Hello World!"));
_ = app.RunAsync();

var httpClient = new HttpClient();

using var tracerProvider = Sdk.CreateTracerProviderBuilder()
    .AddAspNetCoreInstrumentation()
    .Build();

using var meterProvider = Sdk.CreateMeterProviderBuilder()
   .AddAspNetCoreInstrumentation()
   .Build();

for (int i = 0; i < 100000; i++)
{
    var httpResponse = await httpClient.GetAsync("http://localhost:5000").ConfigureAwait(false);
    httpResponse.EnsureSuccessStatusCode();
}

1. I ran the code to be monitored in a for loop to easily distinguish between one-time allocations vs hot-path allocations.
2. I then compared the hot-path allocations for the baseline scenarios and the other scenarios to find out which part of our code caused the allocations (The allocation tool has useful information about call tree, modules, allocation size, etc. which helps with this).

[codecov]

Codecov Report

Merging #4452 (3dd2670) into main (1b9290e) will not change coverage.
The diff coverage is n/a.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #4452   +/-   ##
=======================================
  Coverage   84.09%   84.09%           
=======================================
  Files         311      311           
  Lines       12329    12329           
=======================================
  Hits        10368    10368           
  Misses       1961     1961           

see 5 files with indirect coverage changes

[cijothomas]

Very good!
Would be good to describe the process you followed to break this down, so it'll be good learning for others too, and can be applied elsewhere.