如何在SeriLog接收器中获取当前的HttpContext？

我正在ILogEventSink使用“构建一个简单的接收器”示例创建自己的SeriLog接收器，以记录用户声明中的某些信息。为了访问Core中的HttpContext，我通常会注入的实例，IHttpContextAccessor但是该示例显示了在扩展方法中创建接收器的实例，例如

public class MySink : ILogEventSink
{
    private readonly IFormatProvider _formatProvider;

    public MySink(IFormatProvider formatProvider)
    {
        _formatProvider = formatProvider;
    }

    public void Emit(LogEvent logEvent)
    {
        // How to get HttpContext here?
    }
}

public static class MySinkExtensions
{
    public static LoggerConfiguration MySink(
              this LoggerSinkConfiguration loggerConfiguration,
              IFormatProvider formatProvider = null)
    {
        return loggerConfiguration.Sink(new MySink(formatProvider));
    }
}

...然后使用水槽...

var log = new LoggerConfiguration()
    .MinimumLevel.Information()
    .WriteTo.MySink()
    .CreateLogger();

如何在接收器的Emit方法中访问当前的HttpContext？还是可以通过DI框架创建接收器？

我有一个MVC站点，使用Serilog.AspNetCore v2.1.0针对.Net 4.6.2运行时运行Asp.Net Core 2框架。

更新-解决方法

在@tsimbalar的指针之后，我创建了类似于以下代码的中间件。在我的StartUp.Configure方法中，我会app.UseMiddleware<ClaimsMiddleware>(); 在应用程序身份验证步骤完成后使用来添加它（否则将不会加载任何声明）。

public class ClaimsMiddleware
{
    private static readonly ILogger Log = Serilog.Log.ForContext<ClaimsMiddleware>();
    private readonly RequestDelegate next;

    public ClaimsMiddleware(RequestDelegate next)
    {
        this.next = next ?? throw new ArgumentNullException(nameof(next));
    }

    public async Task Invoke(HttpContext httpContext)
    {
        if (httpContext == null) throw new ArgumentNullException(nameof(httpContext));

        // Get values from claims here
        var myVal = httpContext
                .User
                .Claims
                .Where(x => x.Type == "MyVal")
                .Select(x => x.Value)
                .DefaultIfEmpty(string.Empty)
                .SingleOrDefault();

        using (LogContext.PushProperty("MyVal", myVal))
        {
            try
            {
                await next(httpContext);
            }

            // Never caught, because `LogException()` returns false.
            catch (Exception ex) when (LogException(httpContext, ex)) { }
        }
    }

    private static bool LogException(HttpContext httpContext, Exception ex)
    {
        var logForContext = Log.ForContext("StackTrace", ex.StackTrace);

        logForContext.Error(ex, ex.Message);

        return false;
    }
}