Serial? PSJob? C# Async?

CSharpAsyncAwait.cs

async Task Main()
{
    var client = new HttpClient();
    await Task.WhenAll(Enumerable.Range(0, 100).Select(x => client.GetStringAsync("https://google.com")));
}

PowerShellJob.ps1

Measure-Command {$job = 1..100 | %{Invoke-RestMethod -Method Get -Uri https://google.com &}; Receive-Job $job}

PowerShellSerial.ps1

Measure-Command {1..100 | %{Invoke-RestMethod -Method Get -Uri https://google.com}}

PowerShellWithCSharpAsyncTask.ps1

$csharp = "using System.Linq;
using System.Net.Http;
using System.Threading.Tasks;
public class AsyncRestMethod
{
    public static HttpClient client = new HttpClient();
    public static async Task<string[]> GetStringAsync(string uri, int count) {
        return await Task.WhenAll(Enumerable.Range(0, count).Select(x => client.GetStringAsync(uri)));
    }
}
"
Add-Type -TypeDefinition $csharp -Language CSharp
Measure-Command {[AsyncRestMethod]::GetStringAsync("https://google.com", 100).Result;}

Result.txt

# PowerShellSerial.ps1
TotalSeconds      : 25.7549936

# PowerShellJob.ps1
TotalSeconds      : 15.8745210

# PowerShellWithCSharpAsyncTask.ps1
TotalSeconds      : 0.6443892

# CSharpAsyncAwait.cs
00:00:00.97544477