private static <T> HttpData toHttpData(
            Function<? super T, ? extends ServerSentEvent> converter, T content) {
        final ServerSentEvent sse = converter.apply(content);
        return sse == null ? HttpData.empty() : toHttpData(sse);
    }
Creates a new Server-Sent Events stream of the specified {@code content}.

@param headers the HTTP headers supposed to send
@param sse the {@link ServerSentEvent} object supposed to send as contents
@param trailers the HTTP trailers
core/src/main/java/com/linecorp/armeria/server/streaming/ServerSentEvents.java