LogUserAgentConventionalMiddleware.cs

public class LogUserAgentConventionalMiddleware
{
    private readonly RequestDelegate _next;

    public LogUserAgentConventionalMiddleware(RequestDelegate next)
    {
        _next = next;
    }

    public async Task InvokeAsync(HttpContext context, ILogger<LogUserAgentConventionalMiddleware> logger)
    {
        var userAgent = context.Request.Headers.GetCommaSeparatedValues("User-Agent").LastOrDefault();
        if (userAgent is not null) logger?.LogTrace($"User Agent : {userAgent}");
        await _next(context);
    }
}