Serilog delayed sink initialization example

LateInitExample.cs

using System;
using Serilog;
using Serilog.Configuration;
using Serilog.Core;
using Serilog.Events;

class Program
{
    static void Main(string[] args)
    {
        var signalRSink = new LateInitSink();

        Log.Logger = new LoggerConfiguration()
            .WriteTo.Sink(signalRSink)
            .CreateLogger();

        Log.Information("Sadly, nobody will get this");

        // ... resolve that hub ...
        signalRSink.Init(wt => wt.Console());

        Log.Information("Ah so nice to be loggin' again");
    }
}

class LateInitSink : ILogEventSink, IDisposable
{
    // A lot could obviously be done to improve concurrency in this one :-)
    readonly object _mutex = new object();
    ILogEventSink _sink;

    public void Init(Action<LoggerSinkConfiguration> initSink)
    {
        ILogEventSink inner = null;
        LoggerSinkConfiguration.Wrap(
            new LoggerConfiguration().WriteTo,
            sink => inner = sink,
            initSink);

        if (inner == null)
            throw new InvalidOperationException("Sink not initialized.");

        lock (_mutex)
        {
            if (_sink != null)
                throw new InvalidOperationException("Sink already initialized.");
            _sink = inner;
        }
    }

    public void Emit(LogEvent logEvent)
    {
        lock (_mutex)
            _sink?.Emit(logEvent);
    }

    public void Dispose()
    {
        lock (_mutex)
            (_sink as IDisposable)?.Dispose();
    }
}