public boolean exactlyOnceSourceEnabled() {
        return false;
    }
Whether this worker is configured with exactly-once support for source connectors.
The default implementation returns {@code false} and should be overridden by subclasses
if the worker mode for the subclass provides exactly-once support for source connectors.
@return whether exactly-once support is enabled for source connectors on this worker
connect/runtime/src/main/java/org/apache/kafka/connect/runtime/WorkerConfig.java