@Test
public void metricsSupplierReturnsNull() {

    // given
    SimpleInputBufferPooledObjectOps ops = new SimpleInputBufferPooledObjectOps(
            HeapByteBufferAllocator.INSTANCE,
            TEST_BUFFER_SIZE
    );
    Supplier<String> metricsSupplier = ops.createMetricsSupplier();
    // when
    String result = metricsSupplier.get();
    // then
    assertNull(result);
}