fix(sdk): preserve queued events on stream close

Signed-off-by: Lanre Shittu <136805224+Shizoqua@users.noreply.github.com>

tests/test_sdk_streaming.py

@@ -0,0 +1,24 @@
+"""Tests for SDK streaming primitives."""
+
+import asyncio
+
+import pytest
+
+from nanobot.sdk.streaming import SDKStreamEmitter
+from nanobot.sdk.types import STREAM_EVENT_TEXT_DELTA, StreamEvent
+
+
+@pytest.mark.asyncio
+async def test_close_preserves_events_when_queue_is_full():
+    queue: asyncio.Queue[StreamEvent | object] = asyncio.Queue(maxsize=1)
+    emitter = SDKStreamEmitter(queue)
+    event = StreamEvent(type=STREAM_EVENT_TEXT_DELTA, delta="kept")
+    await emitter.emit(event)
+
+    close_task = asyncio.create_task(emitter.close())
+    await asyncio.sleep(0)
+
+    assert not close_task.done()
+    assert queue.get_nowait() is event
+    await close_task
+    assert queue.qsize() == 1