@ParameterizedTest
    @ArgumentsSource(ClientAndProtocolProvider.class)
    void testExpect100Continue(WebClient client) throws Exception {
        // Makes sure the server sends a '100 Continue' response if 'expect: 100-continue' header exists.
        final AggregatedHttpResponse res =
                client.execute(RequestHeaders.of(HttpMethod.POST, "/echo",
                                                 HttpHeaderNames.EXPECT, "100-continue"),
                               "met expectation")
                      .aggregate().join();

        assertThat(res.status()).isEqualTo(HttpStatus.OK);
        assertThat(res.informationals()).containsExactly(ResponseHeaders.of(100));
        assertThat(res.contentUtf8()).isEqualTo("met expectation");

        // Makes sure the server does not send a '100 Continue' response if 'expect: 100-continue' header
        // does not exists.
        final AggregatedHttpResponse res2 =
                client.execute(RequestHeaders.of(HttpMethod.POST, "/echo"), "without expectation")
                      .aggregate().join();

        assertThat(res2.status()).isEqualTo(HttpStatus.OK);
        assertThat(res2.informationals()).isEmpty();
        assertThat(res2.contentUtf8()).isEqualTo("without expectation");
    }
Similar to {@link #testTimeoutAfterPartialContent(WebClient)}, but tests the case where the service
produces a pooled buffers.
core/src/test/java/com/linecorp/armeria/server/HttpServerTest.java