diagnose produces corrupted jsonl

[mrdrprofuroboros]

Describe the bug
trainer.diagnose has been run with 4 workers, the output generator_call.jsonl file contained:
3T14:07:39.053704"}{"prompt_kwargs": {"s
on one of the lines

To Reproduce
rather sporadic, but I assume some multithreading race condition

Expected behavior
one json per line

[liyin2015]

@mrdrprofuroboros Try to delete all files under this path, and rerun the diagnose. Often it is just invalid json format