Crashes withot logs when using oauth

[Cheshirre]

Description

Crashes without logs when using authorization type "OAUTHBEARER".

client.OAuthBearerSetToken(token.TokenValue, token.Expiration, **null**);

OS -> Ubuntu Linux, MacOS, etc.
Nuget package: Confluent.Kafka, Version=2.3.0.0

How to reproduce

Reproduces on unix OS family: local or in docker container.
Works on windows.

Set principal to null in client.OAuthBearerSetToken(token.TokenValue, token.Expiration, **null**): https://github.com/confluentinc/confluent-kafka-dotnet/blob/master/test/Confluent.Kafka.IntegrationTests/Tests/OauthBearerToken_PublishConsume.cs

Works, when principal set to empty string.

Checklist

Please provide the following information:

• A complete (i.e. we can run it), minimal program demonstrating the problem. No need to supply a project file.
• Confluent.Kafka nuget version.
• Apache Kafka version.
• Client configuration.
• Operating system.
• Provide logs (with "debug" : "..." as necessary in configuration).
• Provide broker log excerpts.
• Critical issue.