When a SourceConnector throws
org.apache.kafka.connect.errors.RetriableException during the poll, connect runtime is supposed to ignore the error and retry per https://cwiki.apache.org/confluence/display/KAFKA/KIP-298%3A+Error+Handling+in+Connect . When the conenctors throw the execption its not handled gracefully.
WorkerSourceTask is catching the exception from wrong package `org.apache.kafka.common.errors`. It is not clear from the API standpoint as to which package the connect framework supports. The safest thing would be to support both the packages even though it's less desirable.