@Override
    public String toString() {
        return "SourceLocation{" +
                "metaId=" + metaId +
                ", childType='" + childType + '\'' +
                ", partIndex=" + partIndex +
                ", recordIndex=" + recordIndex +
                ", dataRange=" + dataRange +
                ", highlight=" + highlights +
                '}';
    }
@return The identifier i.e. strm:part:segment (one based for human use)
stroom-core-shared/src/main/java/stroom/pipeline/shared/SourceLocation.java