Input and output LlmChatCompletionMessages should not have identical timestamps #3582
Description
Description
An issue has been identified with our timestamping of certain Langchain LlmEvents, namely LlmChatCompletionMessage and LlmChatCompletionSummary: "The timestamp for input and output messages in LangChain traces is currently the same because both events are recorded at the end of the span. This may also contribute to ordering and display issues and will need a long-term solution (proposed as adding a separate, accurate timestamp attribute to the custom event data)."
LlmChatCompletionMessages should have unique timestamps for when they were created, not when they were aggregated into a LlmChatCompletionSummary.
This logic should be applied to all LLMs, not just Langchain.
Acceptance Criteria
- UI reflects this timestamp change
- appropriate tests are created