No support for Async messages when using Anthropic instrumentation

[salaboy]

Describe your environment

OS: Mac OS
Python version: Python 3.14.0
Package version: @main

What happened?

There is no support for async messages when instrumenting Anthropic ChatAnthropic, so no spans are created.

Steps to Reproduce

Create a simple example like this one using FastAPI async : https://github.com/salaboy/observing-ai/tree/main/python/langchain/python-merch-store-otel-langchain-official

Expected Result

Async message should be instrumented as Sync messages

Actual Result

No instrumentation happens if Async is used.

Additional context

No response

Would you like to implement a fix?

Yes

Tip

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