Request Linking in asp.net core

In systems where events are processed in several microservices is useful to maintain a request identifier to be able to link logs from each microservice to do some investigation or to measure performance.
So far we have relied in a custom http header and owin middleware to read, add a new segment to this request identifier and then set it in the log4net context so it can be written when logging an event.
For a new asp.net core service I'm working, I have quickly put together new middleware to do the same operation using the documentation, but instead of using log4net I have found that it is easier to use NLog to capture the TraceIdentifier property in the HttpContext.

Middleware

public class TransactionLinkingMiddleware{

private readonly RequestDelegate _next;
public const string ParentTransactionHttpHeader = "Transaction-Link";
public TransactionLinkingMiddleware(RequestDelegate next)
{ 

_next = next;   

}

public Task Invoke(HttpContext context)

{

if (context.Request.Headers.TryGetValue(ParentTransactionHttpHeader, out var headerValues)
                                    && headerValues.Any())

{

context.TraceIdentifier = $"{headerValues.First()}/{context.TraceIdentifier}";
}

// Call the next delegate/middleware in the pipeline

return this._next(context);

}

}

public static class TransactionLinkingMiddlewareExtensions{   

public static IApplicationBuilder UseTransactionLinking(this IApplicationBuilder builder)
                  {        

return builder.UseMiddleware<TransactionLinkingMiddleware>();
} 

}

Startup.cs

public Startup(IConfiguration configuration, IHostingEnvironment env)
{   

Configuration = configuration;    env.ConfigureNLog("NLog.config");
}

public void Configure(IApplicationBuilder app, IHostingEnvironment env,
ILoggerFactory loggerFactory,    IApplicationLifetime applicationLifetime)

{

if (env.IsDevelopment())

{       

app.UseDeveloperExceptionPage();

}

app.UseTransactionLinking();

loggerFactory.AddNLog();

app.UseMvc();

}

NLog.config

<?xml version="1.0" encoding="utf-8" ?><nlog xmlns="http://www.nlog-project.org/schemas/NLog.xsd"
      xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
      autoReload="true"> 

<extensions>

<add assembly="NLog.Web.AspNetCore"/>

</extensions>

<targets>

<target xsi:type="File" name="File"
fileName="${basedir}/logs/log.txt"
layout="TimeStamp=${longdate} Level=${uppercase:${level}} Transaction=${aspnet-TraceIdentifier} Message=${message}" />
</targets> 

<rules>

<logger name="*" minlevel="Debug" writeTo="File" />

</rules>

</nlog> 

NLog.Web and NLog.Web.AspNetCore packages need to be installed https://github.com/NLog/NLog.Web