@Test
    public void disabledCache() {
        final HttpFile uncached = mock(HttpFile.class);
        assertThat(HttpFile.ofCached(uncached, 0)).isSameAs(uncached);
    }
Makes sure zero overhead when {@code maxCachingLength} is {@code 0}.
core/src/test/java/com/linecorp/armeria/server/file/CachingHttpFileTest.java