[Feature Request]: Intercept librdkafka logs

[imalexoff]

Is your request related to a problem you have?

By default, any librdkafka log is written to stderr, but I want to intercept every message and route it to logging framework.

Describe the solution you'd like

For the producer and consumer, you need to configure the log handler:

producer:

var producerBuilder = new ProducerBuilder<byte[], byte[]>(_configuration.GetKafkaConfig())
    .SetLogHandler((_, log) =>
    {
        var logLevel = (LogLevel)log.LevelAs(LogLevelType.MicrosoftExtensionsLogging);
        _logger.Log(logLevel, "librdkafka {Message}", log.Message);
    })

consumer:

var consumerBuilder = new ConsumerBuilder<byte[], byte[]>(kafkaConfig)
    .SetLogHandler((_, log) =>
    {
        var logLevel = (LogLevel)log.LevelAs(LogLevelType.MicrosoftExtensionsLogging);
        _logger.Log(logLevel, "librdkafka {Message}", log.Message);
    })