How to make SEQ display a colored metric badge (highlight) for elapsed time in log messages?

I’m using SEQ for structured logging in my .NET application (Serilog). I want SEQ to display a colored badge (highlight) with the elapsed time (in ms) on the right side of the log message, just like it does for ASP.NET Core health check logs.

Example of what I want: In health check logs, SEQ automatically shows a badge like 423 ms on the right side of the message:

What I tried: I log messages like this:

_logger.LogInformation(
    "Health check GET https://myapp/health succeeded with status code 200 in {Elapsed:0.000} ms",
    405.705);

var position = new { Latitude = 25, Longitude = 134 };
        var elapsedMs = 34;

        _logger.LogInformation("Processed {@Position} in {Elapsed:000} ms.", position, elapsedMs);

How can I make SEQ display the metric badge for my custom logs, just like it does for health checks? I don't get what I need. I tried adding to the signal

This is due to the difference between log events and spans.

Events created using ILogger are log events, which have a single timestamp value.

The events with colored timing bars are spans, and created using System.Diagnostics.Activity. Spans have a start time and an end time, so Seq displays the colored bar showing the elapsed time between the start and end.

You can turn your custom event into a span using either System.Diagnostics.Activity, or SerilogTracing.