protected Stream<Map.Entry<String, ConfigDef.ConfigKey>> configDefsForClass(String typeConfig) {
            final Class<?> cls = (Class<?>) ConfigDef.parseType(typeConfig, props.get(typeConfig), Type.CLASS);
            return getConfigDefFromConfigProvidingClass(typeConfig, cls)
                    .configKeys().entrySet().stream();
        }
Return a stream of configs provided by the {@code configs()} method of class
named in the {@code ...type} parameter of the {@code props}.
connect/runtime/src/main/java/org/apache/kafka/connect/runtime/ConnectorConfig.java