Subscribing to IObservable<T> not type delegate

Question

I inherited a developer's code and I wanted to convert it to c# since the developer made his library in C#. However the only example I have that shows me how to subscribe to this service is in vba which I dont get how its attaching to it.

namespace exampleExcelAddin.Common.Services
{
    public class LogEntry
    {
        public Type Type;
        public string Message;
        public IDictionary<string, object> Meta = new Dictionary<string, object>();
    }

    public interface ILogger
    {
        void LogMessage(string message);

        void LogMessage(Exception exception);
    }

    public static class Logger
    {
        readonly static Lazy<ISubject<LogEntry>> _outputStream = new Lazy<ISubject<LogEntry>>(() => {
            return new ReplaySubject<LogEntry>();
        });

        public static ILogger Create(Type loggerType) => new TypedLogger(loggerType, _outputStream.Value);

        public static IObservable<LogEntry> Output => _outputStream.Value;

        class TypedLogger : ILogger
        {
            readonly ISubject<LogEntry> outputStream;
            readonly Type loggerType;

            internal TypedLogger(Type loggerType, ISubject<LogEntry> outputStream)
            {
                this.loggerType = loggerType;
                this.outputStream = outputStream;
            }

            public void LogMessage(string message)
            {
                outputStream.OnNext(new LogEntry {
                    Type = loggerType,
                    Message = message
                });
            }

            public void LogMessage(Exception exception)
            {
                var logEntry = new LogEntry {
                    Type = loggerType,
                    Message = $"Exception: {exception.Message}"
                };

                logEntry.Meta.Add("StackTrace", exception.StackTrace);

                outputStream.OnNext(logEntry);
            }
        }
    }
}

The working example in vb.net is like so...

 Private Shared log As ILogger = Logger.Create(GetType(myRibbon))
 Logger.Output.Subscribe(
            Sub(entry)
                If MySettings.Default.EnableLogging Then

                    Dim logBuilder As New StringBuilder()
                    logBuilder.
                        AppendLine("-------------------------------------------------").
                        AppendLine($"Type: {entry.Type}").
                        AppendLine($"Message: {entry.Message}")

                    For Each meta In entry.Meta
                        logBuilder.
                            AppendLine($"Meta-Key: {meta.Key}").
                            AppendLine($"Meta-Value: {meta.Value}")
                    Next

                    logBuilder.
                        AppendLine("-------------------------------------------------" & Environment.NewLine)

                    IO.File.AppendAllText(logPath, logBuilder.ToString())
                End If
            End Sub)

Had some help with converting it and keep getting issues with my lambda expression because it is not a delegate type which I understand but keep hitting a wall. Out my element with how to use this services.

Logger.Output.Subscribe(entry => {
                if (Settings.Default.EnableLogging) {
                    var logBuilder = new StringBuilder();
                    logBuilder.AppendLine("-------------------------------------------------").AppendLine($"Type: {entry.Type}").AppendLine($"Message: {entry.Message}");
                    foreach (var meta in entry.Meta) { logBuilder.AppendLine($"Meta-Key: {meta.Key}").AppendLine($"Meta-Value: {meta.Value}"); }
                    _ = logBuilder.AppendLine("-------------------------------------------------" + Environment.NewLine); System.IO.File.AppendAllText(logPath, logBuilder.ToString());
                    }
            });

Answer 1

Figured it out, just needed a package the library uses.

Install-Package System.Reactive -Version 5.0.0