static DependencyLinkV2SpanIterator iterator(Record... records) {
    return new DependencyLinkV2SpanIterator(
        new PeekingIterator<>(List.of(records).iterator()),
        maybeGet(records[0], ZipkinSpans.ZIPKIN_SPANS.TRACE_ID_HIGH, 0L),
        records[0].get(ZipkinSpans.ZIPKIN_SPANS.TRACE_ID));
  }
Service links to empty string are confusing and offer no value.
zipkin-storage/mysql-v1/src/test/java/zipkin2/storage/mysql/v1/DependencyLinkV2SpanIteratorTest.java