feat:add fail_fast parameter to kickoff_for_each_async

[redvelvets]

Currently, kickoff_for_each_async stops execution entirely if any single task fails.
In some scenarios, we want partial failures not to block other tasks, for example:

• Parallel processing of multiple requests where only a few may fail
• Collecting all task results for statistics or further processing

---

Solution (What / How)

• Add a new parameter fail_fast: bool to kickoff_for_each_async, default is True

• Behavior:

  • fail_fast=True → preserve existing behavior: exception immediately aborts execution
  • fail_fast=False → use asyncio.gather(..., return_exceptions=True) to collect all task results, including exceptions

• Backward compatible: default behavior unchanged if parameter is not passed

results = await asyncio.gather(*tasks)

if passed

results = await asyncio.gather(*tasks, return_exceptions=True)

---

Compatibility / Impact

• Default is True, so existing calls behave as before
• When fail_fast=False, the returned list may contain Exception objects, which the caller should handle

[github-actions]

This PR is stale because it has been open for 45 days with no activity.