test(rust): add Bedrock messages streaming e2e

Co-authored-by: Cursor <cursoragent@cursor.com>

tests/test_litellm/anthropic_interface/test_bedrock_rust_bridge_e2e.py

@@ -18,3 +18,21 @@ async def test_bedrock_messages_with_rust() -> None:
 
     assert response["content"][0]["text"]
     assert response["_hidden_params"]["additional_headers"]["x-litellm-rust"] == "true"
+
+
+@pytest.mark.asyncio
+async def test_bedrock_messages_streaming_with_rust() -> None:
+    response = await litellm.anthropic.messages.acreate(
+        model="bedrock/us.anthropic.claude-sonnet-4-5-20250929-v1:0",
+        messages=[{"role": "user", "content": "Say hello"}],
+        max_tokens=20,
+        stream=True,
+        api_key=os.getenv("AWS_BEARER_TOKEN_BEDROCK"),
+        aws_region_name="us-west-2",
+        rust=True,
+    )
+
+    chunks = [chunk async for chunk in response]
+
+    assert chunks
+    assert response._hidden_params["additional_headers"]["x-litellm-rust"] == "true"