@Test public void span_minimum_JSON_V2() {

  MutableSpan span = new MutableSpan();
  span.traceId("7180c278b62e8f6a216a2aea45d08fc9");
  span.id("5b4185666d50f68b");
  assertThat(new String(encoder.encode(span), UTF_8))
      .isEqualTo(
          "{\"traceId\":\"7180c278b62e8f6a216a2aea45d08fc9\",\"id\":\"5b4185666d50f68b\"}");
}