EventListeners are never invoked in `dotnet run app.cs`

[IanKemp]

Description

When a dotnet run app.cs application that uses an EventListener is executed, nothing is ever recorded to that listener.

Reproduction Steps

Create a new C# "console app" solution using top-level statements. Replace the contents of Program.cs with the below. Build the solution so that an executable is generated.

using System.Collections.Concurrent;
using System.Diagnostics.Tracing;

using EventSourceEnumerator eventSourceEnumerator = new();

using HttpClient client = new();
await client.GetAsync("https://example.com");

Console.WriteLine($"Number of events recorded: {eventSourceEnumerator.Events.Count}");

// borrowed from https://www.meziantou.net/listing-all-available-etw-events-in-a-dotnet-application.htm
internal sealed class EventSourceEnumerator : EventListener
{
    public ConcurrentDictionary<string, ConcurrentDictionary<int, EventInfo>> Events { get; } = new();

    public EventSourceEnumerator()
    {
        EventSourceCreated += OnEventSourceCreated;
        EventWritten += OnEventWritten;
    }

    private void OnEventWritten(object? sender, EventWrittenEventArgs e)
    {
        var events = Events[e.EventSource.Name];
        if (events != null)
        {
            if (!events.ContainsKey(e.EventId))
            {
                events.TryAdd(e.EventId, new EventInfo(e.EventId, e.EventName, e.Level, e.PayloadNames?.ToArray() ?? Array.Empty<string>()));
            }
        }
    }

    private void OnEventSourceCreated(object? sender, EventSourceCreatedEventArgs e)
    {
        if (e.EventSource is null)
            return;

        if (!Events.ContainsKey(e.EventSource.Name))
        {
            EnableEvents(e.EventSource, EventLevel.LogAlways);
            Events.TryAdd(e.EventSource.Name, new ConcurrentDictionary<int, EventInfo>());
        }
    }
}

internal sealed record EventInfo(int Id, string? Name, EventLevel Level, string[] PayloadNames);

Expected behavior

Output should be

Number of events recorded: 15

in both cases.

Actual behavior

Correct:

> path\to\solution\directory\bin\Debug\net10.0\Program.exe
Number of events recorded: 15

Incorrect:

> dotnet run --file path\to\solution\directory\Program.cs
Number of events recorded: 0

Regression?

N/A, dotnet run app.cs is new in .NET 10 which is current at the time of writing.

Known Workarounds

None.

Configuration

> dotnet --info
.NET SDK:
 Version:           10.0.103
 Commit:            c2435c3e0f
 Workload version:  10.0.100-manifests.c992be6d
 MSBuild version:   18.0.11+c2435c3e0

Runtime Environment:
 OS Name:     Windows
 OS Version:  10.0.26100
 OS Platform: Windows
 RID:         win-x64
 Base Path:   C:\Program Files\dotnet\sdk\10.0.103\

Other information

No response