## Issue
Closes#5804
## Change
The streaming path used `fromOkHttpResponse(response)`, the converter
written for the synchronous path. That converter calls
`response.body().bytes()` unless the `Content-Type` is
`text/event-stream`, which reads the body to the end and closes it. The
parser then reads the same body, fails with `IOException: closed`, and
the listener receives no events. Servers that stream with another media
type hit this, for example Ollama with `application/x-ndjson`.
`fromOkHttpResponse` is now split into an overload that takes the body
bytes, and the streaming path passes `null`, the same way
`JdkHttpClient` calls `fromJdkResponse(jdkResponse, null)`.
```java
SuccessfulHttpResponse successResponse = fromOkHttpResponse(response, null);
```
The synchronous path is unchanged, and non-2xx responses are still
handled earlier by `readBody(response)`.
`OkHttpClientStreamingTest` serves responses from
`com.sun.net.httpserver.HttpServer`, so it needs no API key. It covers
the streaming path with `application/x-ndjson`, with
`text/event-stream`, with no `Content-Type`, and with a 500 response,
plus the synchronous path with and without `text/event-stream`.
Reverting the fix makes the two non-SSE streaming tests fail with
`IOException: closed`.
The import reordering and line-wrapping in the diff come from
`spotless:apply` (palantir), which reformats the whole file once it is
touched.
## General checklist
- [X] There are no breaking changes (API, behaviour)
- [X] I have added unit and/or integration tests for my change
- [X] The tests cover both positive and negative cases
- [X] I have manually run all the unit and integration tests in the
module I have added/changed, and they are all green
<!-- The two *IT classes in this module (OkHttpClientIT,
OkHttpClientTimeoutIT) require OPENAI_API_KEY and were not run. -->
- [ ] I have manually run all the unit and integration tests in the
[core](https://github.com/langchain4j/langchain4j/tree/main/langchain4j-core)
and
[main](https://github.com/langchain4j/langchain4j/tree/main/langchain4j)
modules, and they are all green
<!-- langchain4j-core was built and tested as part of the -am build and
is green; the langchain4j main module was not run. -->
- [ ] I have added/updated the
[documentation](https://github.com/langchain4j/langchain4j/tree/main/docs/docs)
<!-- Behaviour fix, no documentation change. -->
- [ ] I have added an example in the [examples
repo](https://github.com/langchain4j/langchain4j-examples) (only for
"big" features)
<!-- Bug fix. -->
- [ ] I have added/updated [Spring Boot
starter(s)](https://github.com/langchain4j/langchain4j-spring) (if
applicable)
<!-- No starter is affected. -->
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