[BUG]: ChatSession unnecessarily prevents arbitrary conversation interleaving

[lostmsu]

Description

With asynchronous flows user might ask 2 questions in succession before model has time to answer the first one. This ends up in the following chat pattern:

user: multiply 2 by 3
user: then divide by -1
assistant: 6
assistant: -6

Unfortunately, for some reason ChatSession prevents this while LLAMA 3 instruct models handle such scenario without any issues.

Reproduction Steps

var history = new ChatHistory();
history.AddMessage(AuthorRole.User, "multiply 2 by 3");
history.AddMessage(AuthorRole.User, "then divide by -1");
history.AddMessage(AuthorRole.Assistant, "6");
history.AddMessage(AuthorRole.Assistant, "-6");

Throws ArgumentException twice

Environment & Configuration

• Operating system: Win 11
• .NET runtime version: 8
• LLamaSharp version: 0.14
• CUDA version (if you are using cuda backend): 12
• CPU & GPU device: N/A

Known Workarounds

No response