@Test
    void methodChaining() throws Exception {
        for (Method m : ResponseHeadersBuilder.class.getMethods()) {
            if (m.getReturnType() == HttpHeadersBuilder.class) {
                final Method overriddenMethod =
                        ResponseHeadersBuilder.class.getDeclaredMethod(m.getName(), m.getParameterTypes());
                assertThat(overriddenMethod.getReturnType()).isSameAs(ResponseHeadersBuilder.class);
            }
        }
    }
Makes sure {@link ResponseHeadersBuilder} overrides all {@link HttpHeadersBuilder} methods
with the correct return type.
core/src/test/java/com/linecorp/armeria/common/DefaultResponseHeadersBuilderTest.java