Function encode_stream_with_extensions 

pub fn encode_stream_with_extensions(
    chunks: LlmResponseStream,
    target: WireFormat,
    served_model: Option<String>,
    request_extensions: &ProviderExtensions,
) -> Result<RawEventStream, LlmClientError>

Encodes a response stream, honouring request extensions.

Identical to encode_stream except that Codex tool namespaces recorded on the request are restored on each encoded event.