### Question:
RLP { public static byte[] encodeSet(Set<ByteArrayWrapper> data) { int dataLength = 0; Set<byte[]> encodedElements = new HashSet<>(); for (ByteArrayWrapper element : data) { byte[] encodedElement = RLP.encodeElement(element.getData()); dataLength += encodedElement.length; encodedElements.add(encodedElement); } byte[] listHeader = encodeListHeader(dataLength); byte[] output = new byte[listHeader.length + dataLength]; System.arraycopy(listHeader, 0, output, 0, listHeader.length); int cummStart = listHeader.length; for (byte[] element : encodedElements) { System.arraycopy(element, 0, output, cummStart, element.length); cummStart += element.length; } return output; }  static int decodeInt(byte[] data, int index); static BigInteger decodeBigInteger(byte[] data, int index); static byte[] decodeIP4Bytes(byte[] data, int index); static int getFirstListElement(byte[] payload, int pos); static int getNextElementIndex(byte[] payload, int pos); static void fullTraverse(byte[] msgData, int level, int startPos,
                                    int endPos, int levelToIndex, Queue<Integer> index); static byte getCommandCode(byte[] data); @Nonnull static ArrayList<RLPElement> decode2(@CheckForNull byte[] msgData); static RLPList decodeList(byte[] msgData); @Nullable static RLPElement decode2OneItem(@CheckForNull byte[] msgData, int startPos); @Nonnull static UscAddress parseUscAddress(@Nullable byte[] bytes); @Nonnull static Coin parseCoin(@Nullable byte[] bytes); @Nullable static Coin parseCoinNonNullZero(byte[] bytes); @Nullable static Coin parseSignedCoinNonNullZero(byte[] bytes); static Coin parseCoinNullZero(@Nullable byte[] bytes); @Nullable static BlockDifficulty parseBlockDifficulty(@Nullable byte[] bytes); static byte[] encode(Object input); static byte[] encodeLength(int length, int offset); static byte[] encodeByte(byte singleByte); static byte[] encodeShort(short singleShort); static byte[] encodeInt(int singleInt); static byte[] encodeString(String srcString); static byte[] encodeBigInteger(BigInteger srcBigInteger); static byte[] encodeUscAddress(UscAddress addr); static byte[] encodeCoin(@Nullable Coin coin); static byte[] encodeCoinNonNullZero(@CheckForNull Coin coin); static byte[] encodeSignedCoinNonNullZero(@CheckForNull Coin coin); static byte[] encodeCoinNullZero(Coin coin); static byte[] encodeBlockDifficulty(BlockDifficulty difficulty); static byte[] encodeElement(@Nullable byte[] srcData); static byte[] encodeListHeader(int size); static byte[] encodeLongElementHeader(int length); static byte[] encodeSet(Set<ByteArrayWrapper> data); static byte[] encodeList(byte[]... elements);  }### Answer:
@Test public void testEncodeSet_2(){ Set<ByteArrayWrapper> data = new HashSet<>(); byte[] setEncoded = encodeSet(data); assertEquals("c0", Hex.toHexString(setEncoded)); }