public Builder setAbstract(boolean isAbstract) {
            this.isAbstract = isAbstract;
            return this;
        }
Sets the {@code abstract} property of the projection.

<p>Abstract projections do not directly create any artifacts.

@param isAbstract Set to true to mark as abstract.
@return Returns the builder.
smithy-build/src/main/java/software/amazon/smithy/build/model/ProjectionConfig.java