SkyApm Log exception

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• Why do you submit this issue?
• Question or discussion
• [* ] Bug
• Requirement
• Feature or performance improvement

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Question

• What do you want to know?

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Bug

• Which version of SkyWalking, OS and .NET Runtime?

• Which company or project?

• What happen? If possible, provide a way for reproducing the error. e.g. demo application, component version.

Unhandled exception. System.AggregateException: An error occurred while writing to logger(s). (Object reference not set to an instance of an object.)
 ---> System.NullReferenceException: Object reference not set to an instance of an object.
   at SkyApm.Transport.SegmentContextMapper.Map(SegmentContext segmentContext)
   at SkyApm.Transport.LoggerContextContextMapper.Map(LoggerContext loggerContext)
   at SkyApm.Transport.AsyncQueueSkyApmLogDispatcher.Dispatch(LoggerContext loggerContext)
   at SkyApm.Diagnostics.MSLogging.SkyApmLogger.Log[TState](LogLevel logLevel, EventId eventId, TState state, Exception exception, Func`3 formatter)
   at Microsoft.Extensions.Logging.Logger.<Log>g__LoggerLog|12_0[TState](LogLevel logLevel, EventId eventId, ILogger logger, Exception exception, Func`3 formatter, List`1& exceptions, TState& state)
   --- End of inner exception stack trace ---
   at Microsoft.Extensions.Logging.Logger.ThrowLoggingError(List`1 exceptions)
   at Microsoft.Extensions.Logging.Logger.Log[TState](LogLevel logLevel, EventId eventId, TState state, Exception exception, Func`3 formatter)
   at Microsoft.Extensions.Logging.Logger`1.Microsoft.Extensions.Logging.ILogger.Log[TState](LogLevel logLevel, EventId eventId, TState state, Exception exception, Func`3 formatter)
   at Microsoft.Extensions.Logging.LoggerExtensions.Log(ILogger logger, LogLevel logLevel, EventId eventId, Exception exception, String message, Object[] args)
   at Microsoft.Extensions.Logging.LoggerExtensions.LogInformation(ILogger logger, String message, Object[] args)
   at DotNetCore.CAP.Processor.CapProcessingServer.Dispose()
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.ServiceProviderEngineScope.DisposeAsync()
--- End of stack trace from previous location ---
   at Microsoft.Extensions.Hosting.Internal.Host.<DisposeAsync>g__DisposeAsync|16_0(Object o)
   at Microsoft.Extensions.Hosting.Internal.Host.DisposeAsync()
   at Microsoft.Extensions.Hosting.HostingAbstractionsHostExtensions.RunAsync(IHost host, CancellationToken token)
   at Microsoft.Extensions.Hosting.HostingAbstractionsHostExtensions.Run(IHost host)
   at Microsoft.AspNetCore.Builder.WebApplication.Run(String url)

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Requirement or improvement

• Please describe about your requirements or improvement suggestions.

[liuhaoyang]

I have removed the 2.1.0 release until this issue is fixed.

[liuhaoyang]

it seem like a critical fault it make logger broken when we do not have init EntrySegment Just happen Like:

1. some module that do not use skyapm like quartz,hangfire and so on
2. BackgroundService、HostService

@liuhaoyang @GeorGeWzw any suggestions?

I just re-reviewed the code LoggerContextContextMapper.cs#L34 should check if SegmentContext is null before mapping SegmentContext to segmentRequest