public ClassLoader loader() {
        return loader;
    }
Container for connectors which is responsible for managing their lifecycle (e.g. handling startup,
shutdown, pausing, etc.). Internally, we manage the runtime state of the connector and transition according
to target state changes. Note that unlike connector tasks, the connector does not really have a "pause"
state which is distinct from being stopped. We therefore treat pause operations as requests to momentarily
stop the connector, and resume operations as requests to restart it (without reinitialization). Connector
failures, whether in initialization or after startup, are treated as fatal, which means that we will not attempt
to restart this connector instance after failure. What this means from a user perspective is that you must
use the /restart REST API to restart a failed task. This behavior is consistent with task failures.
<p>
Note that this class is NOT thread-safe.
connect/runtime/src/main/java/org/apache/kafka/connect/runtime/WorkerConnector.java