@Test
public void testHexDump() {

    assertEquals("", ByteBufUtil.hexDump(EMPTY_BUFFER));
    ByteBuf buffer = wrappedBuffer(new byte[]{ 0x12, 0x34, 0x56 });
    assertEquals("123456", ByteBufUtil.hexDump(buffer));
    buffer.release();
    buffer = wrappedBuffer(new byte[]{
            0x12, 0x34, 0x56, 0x78,
            (byte) 0x90, (byte) 0xAB, (byte) 0xCD, (byte) 0xEF
    });
    assertEquals("1234567890abcdef", ByteBufUtil.hexDump(buffer));
    buffer.release();
}