* very early, while there is no session created yet.
 *
 * @since 4.0.0
 */
@Experimental
@Consumer
@Named
public interface PropertyContributor extends SpiService {
    /**
     * Invoked just before session is created with a mutable map that carries collected user properties so far.
     *

import org.apache.maven.api.di.Named;
import org.apache.maven.api.spi.PropertyContributor;

/**
 * Hack: to circumvent sisu/plexus/di stuff.
 */
@Named
public final class PropertyContributorsHolder {
    private final Map<String, PropertyContributor> propertyContributors;

    @Inject
    public PropertyContributorsHolder(Map<String, PropertyContributor> propertyContributors) {
        this.propertyContributors = propertyContributors;

        ProtoSession protoSession = context.protoSession;
        for (PropertyContributor propertyContributor : context.lookup
                .lookup(PropertyContributorsHolder.class)
                .getPropertyContributors()
                .values()) {
            protoSession = protoSession.toBuilder()
                    .withUserProperties(propertyContributor.contribute(protoSession))
                    .build();
        }