@Test public void parseBytes_unsupportedFieldIdFirst_toNull() {

  assertThat(TraceContextBinaryFormat.parseBytes(new byte[] {
    0,
    4, 127, -1, -1, -1, -1, -1, -1, -1, -128, 0, 0, 0, 0, 0, 0, 0, // bad field number
    1, -1, -1, -1, -1, -1, -1, -1, -1,
    2, 1
  }, null)).isNull();
}