@JsonIgnore
    public String getIdentifierString() {
        // Convert to one-based
        return metaId + ":" + (partIndex + 1) + ":" + (recordIndex + 1);
    }
@return The identifier i.e. strm:part:segment (one based for human use)
stroom-core-shared/src/main/java/stroom/pipeline/shared/SourceLocation.java