Function replay_stream_events 

pub fn replay_stream_events(
    events: Vec<LlmResponseStreamEvent>,
) -> LlmResponseStream

Replays previously buffered events as a stream, preserving their provider payloads.

Pair with LlmResponse::into_agg_retaining_events when a caller had to buffer a response but must still serve the original bytes downstream. Unlike AggLlmResponse::into_stream, this is lossless: preservation survives, so the outbound codec can emit a faithful same-format response instead of a synthetic one.