[Feature] Support concurrency for streamify

[jd02904]

What feature would you like to see?

I am running an async dspy app in fast api and running into the below error when processing more than one request at a time:

2025/05/05 17:22:14 WARNING dspy.utils.callback: Error when applying callback <dspy.streaming.messages.StatusStreamingCallback object at 0x32ce150d0>'s end handler on function __call__: This function can only be run from an AnyIO worker thread.
2025/05/05 17:22:14 WARNING dspy.utils.callback: Error when calling callback <dspy.streaming.messages.StatusStreamingCallback object at 0x32ce150d0>: This function can only be run from an AnyIO worker thread

The app runs fine with just one request after the other.
Has this been encountered before? Is there a quick fix to this or is this a limitation of streamify?

Would you like to contribute?

• Yes, I'd like to help implement this.
• No, I just want to request it.

Additional Context

No response