List<List<Span>> awaitSpans(int count) {
    await().untilAsserted(() -> { // wait for spans
      List<List<Span>> traces = inMemoryStorage().getTraces();
      long received = traces.stream().mapToLong(List::size).sum();
      assertThat(inMemoryStorage().acceptedSpanCount())
        .withFailMessage("Wanted %s spans: got %s. Current traces: %s", count, received, traces)
        .isGreaterThanOrEqualTo(count);
    });
    return inMemoryStorage().getTraces();
  }
The {@code toString()} of {@link Component} implementations appear in health check endpoints.
Since these are likely to be exposed in logs and other monitoring tools, care should be taken
to ensure {@code toString()} output is a reasonable length and does not contain sensitive
information.
zipkin-server/src/test/java/zipkin2/server/internal/brave/ITZipkinSelfTracing.java