public final String toBitString(long value) {
        return toBitString(value, 64);
    }
@Test
    public void testToBitString() {
        assertEquals("0010101010101010101010101010101010101010101010101010101010101010", bitUtil.toBitString(Long.MAX_VALUE / 3));
        assertEquals("0111111111111111111111111111111111111111111111111111111111111111", bitUtil.toBitString(Long.MAX_VALUE));

        assertEquals("00101010101010101010101010101010", bitUtil.toBitString(bitUtil.fromInt(Integer.MAX_VALUE / 3)));

        assertEquals("10000000000000000000000000000000", bitUtil.toBitString(1L << 63, 32));
        assertEquals("00000000000000000000000000000001", bitUtil.toBitString((1L << 32), 32));
    }