Provide a way to unsubscribe from LogHandler/ErrorHandler

[horato]

Description

There is currently no way to remove the referenced Actions from Producer/Consumer which might cause a memory leak.

var producer = new ProducerBuilder<string, string>(producerConfig)
		.SetLogHandler(LogHandler)
		.Build();

How to reproduce

Confluent.Kafka 2.3.0
librdkafka 2.3.0

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.

[quixoticaxis]

What is the scenario for memory leaking? When you're done with the producer, the handlers would go with it.