fix(bedrock): stream events incrementally instead of buffering (#1989)

Fixes #1986

`_run_converse_stream` used `list()` to collect all stream events before
returning. This blocked the caller until the full response was ready.

Replaced with an `asyncio.Queue` bridge so events are forwarded as they
arrive from boto3.

Signed-off-by: mesutoezdil <mesudozdil@gmail.com>
Co-authored-by: J.M. Huibonhoa <jmhbh@users.noreply.github.com>

Author: mesutoezdil

python/packages/kagent-adk/src/kagent/adk/models/_bedrock.py

@@ -318,21 +318,32 @@ async def generate_content_async(
         if self.additional_model_request_fields:
             kwargs["additionalModelRequestFields"] = self.additional_model_request_fields
 
-        def _run_converse_stream(**kw):
-            resp = client.converse_stream(**kw)
-            return list(resp.get("stream", []))
-
         try:
             if stream:
-                stream_body = await asyncio.to_thread(_run_converse_stream, **kwargs)
+                q: asyncio.Queue = asyncio.Queue()
+                loop = asyncio.get_running_loop()
+
+                def _produce():
+                    try:
+                        resp = client.converse_stream(**kwargs)
+                        for event in resp.get("stream", []):
+                            loop.call_soon_threadsafe(q.put_nowait, event)
+                    except Exception as exc:
+                        loop.call_soon_threadsafe(q.put_nowait, exc)
+                    finally:
+                        loop.call_soon_threadsafe(q.put_nowait, None)
+
+                loop.run_in_executor(None, _produce)
 
                 aggregated_text = ""
                 tool_uses: dict[str, dict] = {}  # toolUseId -> {name, input_json}
                 current_tool_id: Optional[str] = None
                 stop_reason = "end_turn"
                 usage_metadata: Optional[types.GenerateContentResponseUsageMetadata] = None
 
-                for event in stream_body:
+                while (event := await q.get()) is not None:
+                    if isinstance(event, Exception):
+                        raise event
                     if "contentBlockStart" in event:
                         start = event["contentBlockStart"].get("start", {})
                         if "toolUse" in start: