public ExactlyOnceSupport exactlyOnceSupport(Map<String, String> connectorConfig) {
        return null;
    }
Signals whether the connector supports exactly-once semantics with a proposed configuration.
Connector authors can assume that worker-level exactly-once support is enabled when this method is invoked.

<p>For backwards compatibility, the default implementation will return {@code null}, but connector authors are
strongly encouraged to override this method to return a non-null value such as
{@link ExactlyOnceSupport#SUPPORTED SUPPORTED} or {@link ExactlyOnceSupport#UNSUPPORTED UNSUPPORTED}.

<p>Similar to {@link #validate(Map) validate}, this method may be called by the runtime before the
{@link #start(Map) start} method is invoked when the connector will be run with exactly-once support.

@param connectorConfig the configuration that will be used for the connector.
@return {@link ExactlyOnceSupport#SUPPORTED} if the connector can provide exactly-once support with the given
configuration, and {@link ExactlyOnceSupport#UNSUPPORTED} if it cannot. If this method is overridden by a
connector, should not be {@code null}, but if {@code null}, it will be assumed that the connector cannot provide
exactly-once semantics.
@since 3.3
connect/api/src/main/java/org/apache/kafka/connect/source/SourceConnector.java