Enrich.WithCaller()

Program.cs

using System;
using System.Diagnostics;
using System.Linq;
using System.Runtime.CompilerServices;
using Serilog;
using Serilog.Configuration;
using Serilog.Core;
using Serilog.Events;

namespace ConsoleApp24
{
    class CallerEnricher : ILogEventEnricher
    {
        public void Enrich(LogEvent logEvent, ILogEventPropertyFactory propertyFactory)
        {
            var skip = 3;
            while (true)
            {
                var stack = new StackFrame(skip);
                if (stack.GetMethod() is not { } method)
                {
                    return;
                }

                if (method.DeclaringType.Assembly != typeof(Log).Assembly)
                {
                    var caller = $"{method.DeclaringType.Name}.{method.Name}({string.Join(", ", method.GetParameters().Select(pi => pi.ParameterType.FullName))})";
                    logEvent.AddOrUpdateProperty(new LogEventProperty("SourceContext", new ScalarValue(caller)));
                    return;
                }

                skip++;
            }
        }
    }

    class Program
    {
        static void Main(string[] args)
        {
            Log.Logger = new LoggerConfiguration()
                .Enrich.With<CallerEnricher>()
                .WriteTo.Console()
                .CreateLogger();

            Log.Information("Hello, world!");

            SayGoodbye();

            Log.CloseAndFlush();
        }
        
        [MethodImpl(MethodImplOptions.NoInlining)]
        static void SayGoodbye()
        {
            Log.Information("Goodbye!");
        }
    }
}