[nima] content is not sent if using OutputStream

[wojtask9]

Environment Details

• Helidon Version: 4.0.0-ALPHA6
• Helidon SE
• JDK version: OpenJDK 64-Bit Server VM Temurin-20+36 (build 20+36, mixed mode, sharing)
• OS: Linux

---

Problem Description

When content length is less than 512 bytes then output is wrongly send to client.

Steps to reproduce

test:

public void routing(HttpRouting.Builder routing) {

        int LENGTH = 511;

        routing.get("/test_stream", (req, res) -> {
            String content ="a".repeat(LENGTH);

            InputStream in = new ByteArrayInputStream(content.getBytes());
            in.transferTo(res.outputStream());
        });

        routing.get("/test_string", (req, res) -> {
            String content ="a".repeat(LENGTH);

            res.send(content.getBytes());
        });
}

output:

send not using OutputStream

curl -k -i  -X GET https://localhost:8080/test_string
HTTP/1.1 200 OK
Date: Wed, 19 Apr 2023 13:31:16 +0200
Connection: keep-alive
Content-Length: 511

aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa

send using OutputStream

curl -k -i  -X GET https://localhost:8080/test_stream
HTTP/1.1 200 OK
Date: Wed, 19 Apr 2023 13:31:13 +0200
Connection: keep-alive
Content-Length: 0

When we increase LENGTH to 512 everything works correct.

[wojtask9]

not sure if this problem is related to #6501

[spericas]

@wojtask9 Could you try explicitly flushing the output stream? There's new buffering to avoid some problems. See #6509.

[wojtask9]

@spericas

OutputStream os = res.outputStream();
in.transferTo(os);
os.flush();

With explicit flush everything works :)

[spericas]

@wojtask9 I will create a PR to do auto-flushing at the end for convenience.