@Override
    public String toString() {
        return "com.alibaba.csp.sentinel.spi.SpiLoader[" + service.getName() + "]";
    }
@Test
    public void testToString() {
        SpiLoader spiLoader = SpiLoader.of(ProcessorSlot.class);
        assertEquals("com.alibaba.csp.sentinel.spi.SpiLoader[com.alibaba.csp.sentinel.slotchain.ProcessorSlot]"
            , spiLoader.toString());
    }