public static Integer getBodySizeIfKnown(ZuulMessage msg) {
        final Integer bodySize = getContentLengthIfPresent(msg);
        if (bodySize != null) {
            return bodySize;
        }
        if (msg.hasCompleteBody()) {
            return msg.getBodyLength();
        }
        return null;
    }
@Test
    void getBodySizeIfKnown_returnsContentLengthValue() {
        SessionContext context = new SessionContext();
        Headers headers = new Headers();
        headers.add(com.netflix.zuul.message.http.HttpHeaderNames.CONTENT_LENGTH, "23450");
        ZuulMessage msg = new ZuulMessageImpl(context, headers);
        assertThat(HttpUtils.getBodySizeIfKnown(msg)).isEqualTo(Integer.valueOf(23450));
    }