Fixups to ProducerConfig
Fixups to ProducerConfig

Closes #87
Closes #99

raisemarketplace/sarama,DataDog/sarama,Shopify/sarama,LastManStanding/sarama,cep21/sarama,gyroscope-innovations/legacy_sarama,jimmykuo/sarama,mailgun/sarama,kraveio/sarama,Shopify/sarama,aybabtme/sarama,VividCortex/sarama,jepst/sarama,betable/sarama,uovobw/sarama,winlinvip/sarama,jimmykuo/sarama,LastManStanding/sarama,HelixEducation/sarama,crast/sarama,yangfan876/sarama,HelixEducation/sarama,kmiku7/sarama,kraveio/sarama,gyroscope-innovations/legacy_sarama,scalingdata/sarama,vrischmann/sarama,winlinvip/sarama,crast/sarama,VividCortex/sarama,remerge/sarama,uovobw/sarama,scalingdata/sarama,pronix/sarama,kmiku7/sarama,rafrombrc/sarama,mailgun/sarama,Neuw84/sarama,pronix/sarama,vrischmann/sarama,DataDog/sarama,cep21/sarama,jepst/sarama,remerge/sarama,Neuw84/sarama,raisemarketplace/sarama,yangfan876/sarama,betable/sarama,aybabtme/sarama,rafrombrc/sarama