Is your feature request related to a problem? Please describe.

Improvement

SDK users sometimes need to know which JSON-RPC method is being
processed to adjust their implementation, e.g.:

• If the method is message/send, they may want to use
  invoke()/run() when calling their LLM API, and
  stream()/run_streamed() for message/stream.

Describe the solution you'd like

Added a method field to ServerCallContext.state, similar to
headers.

Describe alternatives you've considered

No response

Additional context

Added in the python SDK by
a2aproject/a2a-python@d62df7a

Code of Conduct

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