public static <K, V> MapCoder<K, V> of(Coder<K> keyCoder, Coder<V> valueCoder) {
    return new MapCoder<>(keyCoder, valueCoder);
  }
@Test
  public void testStructuralValueDecodeEncodeEqual() throws Exception {
    MapCoder<byte[], Integer> coder = MapCoder.of(ByteArrayCoder.of(), VarIntCoder.of());
    Map<byte[], Integer> value = Collections.singletonMap(new byte[] {1, 2, 3, 4}, 1);
    CoderProperties.structuralValueDecodeEncodeEqual(coder, value);
  }