@Test void idempotent() {
    CollectorSampler sampler1 = CollectorSampler.create(0.1f);
    CollectorSampler sampler2 = CollectorSampler.create(0.1f);

    assertThat(lotsOfSpans().filter(s -> sampler1.isSampled(s.traceId(), false)).toArray())
        .containsExactly(
            lotsOfSpans().filter(s -> sampler2.isSampled(s.traceId(), false)).toArray());
  }
The collector needs to apply the same decision to incremental updates in a trace.
zipkin-collector/core/src/test/java/zipkin2/collector/CollectorSamplerTest.java