@JsonIgnore
    public DataRange getFirstHighlight() {
        return highlights != null && !highlights.isEmpty()
                ? highlights.get(0)
                : null;
    }
Most users of {@link SourceLocation} are only expecting one highlight so this is a helper
for them. Returns null if there isn't one.
stroom-core-shared/src/main/java/stroom/pipeline/shared/SourceLocation.java