Benchmarking memory traffic from the while loop inside async CE

Program.fs

open System
open BenchmarkDotNet.Attributes
open BenchmarkDotNet.Running
open BenchmarkDotNet.Jobs
open FSharp.Control.Tasks.V2

[<SimpleJob(RuntimeMoniker.NetCoreApp31); MemoryDiagnoser>]
type Test() =

    [<Params(100, 1000, 10000)>]
    member val Length = 0 with get, set

    [<Benchmark(Baseline=true)>]
    member this.WhileAsync() =
        async {
            let mutable i = 0
            while i < this.Length do
                i <- i + 1
            return i
        } |> Async.RunSynchronously


    [<Benchmark>]
    member this.WhileTask () =
        (task {
            let mutable i = 0
            while i < this.Length do
                i <- i + 1
            return i
        }).Result


    [<Benchmark>]
    member this.Rec () =
        async {
            let mutable i = 0
            let rec while' () =
                if i = this.Length 
                then i
                else
                  i <- i + 1
                  while' ()
            return while' ()
        } |> Async.RunSynchronously

        
[<EntryPoint>]
let main _ =
    BenchmarkRunner.Run<Test>() |> ignore
    0

Result.md

BenchmarkDotNet=v0.12.0, OS=Windows 10.0.18362
Intel Core i7-4790K CPU 4.00GHz (Haswell), 1 CPU, 8 logical and 4 physical cores
.NET Core SDK=3.1.102
  [Host]     : .NET Core 3.1.2 (CoreCLR 4.700.20.6602, CoreFX 4.700.20.6702), X64 RyuJIT DEBUG
  Job-LGDGOM : .NET Core 3.1.2 (CoreCLR 4.700.20.6602, CoreFX 4.700.20.6702), X64 RyuJIT

Runtime=.NET Core 3.1  

Method	Length	Mean	Error	StdDev	Ratio	RatioSD	Gen 0	Gen 1	Gen 2	Allocated
WhileAsync	100	4,444.5 ns	87.46 ns	136.16 ns	1.00	0.00	1.8539	-	-	7776 B
WhileTask	100	1,369.3 ns	27.08 ns	42.96 ns	0.31	0.02	0.8259	-	-	3456 B
Rec	100	403.7 ns	7.97 ns	10.64 ns	0.09	0.00	0.2122	-	-	888 B
WhileAsync	1000	40,355.5 ns	786.42 ns	1,127.86 ns	1.00	0.00	15.7471	-	-	65880 B
WhileTask	1000	12,482.6 ns	249.24 ns	277.03 ns	0.31	0.01	7.7057	-	-	32256 B
Rec	1000	1,804.6 ns	29.19 ns	25.88 ns	0.04	0.00	0.2117	-	-	888 B
WhileAsync	10000	411,709.7 ns	7,370.42 ns	6,894.30 ns	1.00	0.00	154.2969	-	-	646920 B
WhileTask	10000	128,999.1 ns	2,088.37 ns	1,953.46 ns	0.31	0.01	76.4160	-	-	320257 B
Rec	10000	15,223.4 ns	161.78 ns	151.33 ns	0.04	0.00	0.1831	-	-	888 B