public static String generateTransactionHashHexEncoded(
            RawTransaction rawTransaction, Credentials credentials) {
        return Numeric.toHexString(generateTransactionHash(rawTransaction, credentials));
    }
@Test
    public void testGenerateEip155TransactionHash() {
        assertEquals(
                generateTransactionHashHexEncoded(
                        TransactionEncoderTest.createContractTransaction(),
                        (byte) 1,
                        SampleKeys.CREDENTIALS),
                ("0x568c7f6920c1cee8332e245c473657b9c53044eb96ed7532f5550f1139861e9e"));
    }