private void collectFulfillmentRequests(List<RequestSpec<K>> requests) {
        collectRequests(
            requests,
            fulfillmentMap,
            (keys, scope) -> handler.buildRequest(scope.destinationBrokerId, keys)
        );
    }
Callback that is invoked when a `Call` is failed.
clients/src/main/java/org/apache/kafka/clients/admin/internals/AdminApiDriver.java