void handleStorageError(List<Span> spans, Throwable e, Callback<Void> callback) {
    metrics.incrementSpansDropped(spans.size());
    // The exception could be related to a span being huge. Instead of filling logs,
    // print trace id, span id pairs
    handleError(e, () -> appendSpanIds(spans, new StringBuilder("Cannot store spans ")), callback);
  }
When storing spans, an exception can be raised before or after the fact. This adds context of
span ids to give logs more relevance.
zipkin-collector/core/src/main/java/zipkin2/collector/Collector.java