void call(Call call, long now) {
            if (hardShutdownTimeMs.get() != INVALID_SHUTDOWN_TIME) {
                log.debug("Cannot accept new call {} when AdminClient is closing.", call);
                call.handleFailure(new IllegalStateException("Cannot accept new calls when AdminClient is closing."));
            } else if (metadataManager.usingBootstrapControllers() &&
                    (!call.nodeProvider.supportsUseControllers())) {
                call.fail(now, new UnsupportedEndpointTypeException("This Admin API is not " +
                    "yet supported when communicating directly with the controller quorum."));
            } else {
                enqueue(call, now);
            }
        }
Initiate a new call.

This will fail if the AdminClient is scheduled to shut down.

@param call      The new call object.
@param now       The current time in milliseconds.
clients/src/main/java/org/apache/kafka/clients/admin/KafkaAdminClient.java