fix issue https://github.com/openai/openai-agents-python/issues/442
below is an example to overwrite include_usage
```
result = Runner.run_streamed(
agent,
"Write a haiku about recursion in programming.",
run_config=RunConfig(
model_provider=CUSTOM_MODEL_PROVIDER,
model_settings=ModelSettings(include_usage=True)
),
)
```