Logged with log4net but log lines never appear in stackdriver.

Like this user report on stack overflow, https://stackoverflow.com/questions/48962850/cant-write-log-entry-with-google-clouds-log4net-integration I followed the instructions here: https://googlecloudplatform.github.io/google-cloud-dotnet/docs/Google.Cloud.Logging.Log4Net/index.html Wrote this code: https://github.com/SurferJeffAtGoogle/csharp-docs-samples/tree/log4net/logging/api/Log4NetSample And ran it:

~/gitrepos/dotnet-docs-samples/logging/api/Log4NetSample$ dotnet run
log4net: log4net assembly [log4net, Version=2.0.8.0, Culture=neutral, PublicKeyToken=669e0ddf0bb1aa2a]. (.NET Framework [.NET Core 4.6.0.0] on Linux 4.9.0-5-amd64 #1 SMP Debian 4.9.65-3+deb9u2 (2018-01-04))
log4net: defaultRepositoryType [log4net.Repository.Hierarchy.Hierarchy]
log4net: Creating repository for assembly [Log4NetSample, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null]
log4net: Assembly [Log4NetSample, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null] Loaded From [Not supported on .NETCore]
log4net: Assembly [Log4NetSample, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null] does not have a RepositoryAttribute specified.
log4net: Assembly [Log4NetSample, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null] using repository [log4net-default-repository] and repository type [log4net.Repository.Hierarchy.Hierarchy]
log4net: Creating repository [log4net-default-repository] using type [log4net.Repository.Hierarchy.Hierarchy]
log4net: configuring repository [log4net-default-repository] using file [log4net.xml]
log4net: configuring repository [log4net-default-repository] using stream
log4net: loading XML configuration
log4net: Configuring Repository [log4net-default-repository]
log4net: Configuration update mode [Merge].
log4net: Logger [root] Level string is [ALL].
log4net: Logger [root] level set to [name="ALL",value=-2147483648].
log4net: Loading Appender [CloudLogger] type: [Google.Cloud.Logging.Log4Net.GoogleStackdriverAppender,Google.Cloud.Logging.Log4Net]
log4net: Converter [message] Option [] Format [min=-1,max=2147483647,leftAlign=False]
log4net: Converter [newline] Option [] Format [min=-1,max=2147483647,leftAlign=False]
log4net: Setting Property [ConversionPattern] to String value [%-4timestamp [%thread] %-5level %logger %ndc - %message]
log4net: Converter [timestamp] Option [] Format [min=4,max=2147483647,leftAlign=True]
log4net: Converter [literal] Option [ [] Format [min=-1,max=2147483647,leftAlign=False]
log4net: Converter [thread] Option [] Format [min=-1,max=2147483647,leftAlign=False]
log4net: Converter [literal] Option [] ] Format [min=-1,max=2147483647,leftAlign=False]
log4net: Converter [level] Option [] Format [min=5,max=2147483647,leftAlign=True]
log4net: Converter [literal] Option [ ] Format [min=-1,max=2147483647,leftAlign=False]
log4net: Converter [logger] Option [] Format [min=-1,max=2147483647,leftAlign=False]
log4net: Converter [literal] Option [ ] Format [min=-1,max=2147483647,leftAlign=False]
log4net: Converter [ndc] Option [] Format [min=-1,max=2147483647,leftAlign=False]
log4net: Converter [literal] Option [ - ] Format [min=-1,max=2147483647,leftAlign=False]
log4net: Converter [message] Option [] Format [min=-1,max=2147483647,leftAlign=False]
log4net: Setting Property [Layout] to object [log4net.Layout.PatternLayout]
log4net: Setting Property [ProjectId] to String value [surferjeff-test2]
log4net: Setting Property [LogId] to String value [console]
log4net: Created Appender [CloudLogger]
log4net: Adding appender named [CloudLogger] to logger [root].
log4net: Hierarchy Threshold []
Hello World!

But nothing appears in my stackdriver logs:

[jskeet]

Reopened - Chris, are you okay to have a look at this?

[chrisdunelm]

OK, so this is broken in two ways:

1. The LogManager.Flush call does absolutely nothing in .NETStandard projects; and this sample is .NETStandard, so it cannot work.
2. On full .NET framework code, LogManager.Flush() requires the appender to implement IFlushable, which GoogleStackdriverAppender does not.

I will add IFlushable support in a PR soon.