* @return the mutable transformerContext
     */
    TransformerContext initialize(ModelBuildingRequest request, ModelProblemCollector problems);

    /**
     * The immutable transformerContext, can be used after the buildplan is finished.
     *
     * @return the immutable transformerContext
     */
    TransformerContext build();

import org.apache.maven.model.building.DefaultTransformerContext.GAKey;
import org.apache.maven.model.building.DefaultTransformerContext.Holder;

/**
 * Builds up the transformer context.
 * After the buildplan is ready, the build()-method returns the immutable context useful during distribution.
 * This is an inner class, as it must be able to call readRawModel()
 *
 * @since 4.0.0