synchronized void onNewMetadataImage(MetadataImage newImage, MetadataDelta delta) {
        this.coordinator.onNewMetadataImage(newImage, delta);
    }
A new metadata image is available. This is only called after {@link SnapshottableCoordinator#onLoaded(MetadataImage)}
is called to signal that the coordinator has been fully loaded.

@param newImage  The new metadata image.
@param delta     The delta image.
group-coordinator/src/main/java/org/apache/kafka/coordinator/group/runtime/SnapshottableCoordinator.java