@Override
            protected HttpObject filter(HttpObject obj) {
                if (obj instanceof HttpData) {
                    requestContentPreviewer.onData((HttpData) obj);
                }
                return obj;
            }
Sets up the request {@link ContentPreviewer} to set
{@link RequestLogBuilder#requestContentPreview(String)} when the preview is available.
core/src/main/java/com/linecorp/armeria/internal/logging/ContentPreviewingUtil.java