Support cancellation

[startime-h]

ERROR McpServerSession - - No handler registered for notification method: notifications/cancelled

[tzolov]

Thanks for highlighting this @startime-h!
The SDK doesn't implement cancellation capabilities yet. We can start with basic, e.g. ignore cancellation handlers (on client and server side).

To build more meaningful cancelation handlers we need to better understand the common use cases. Can you please elaborate on your use case?

[CrazyHZM]

@tzolov Sending a cancellation notification when a request times out is a usage scenario.
See #147

[MaxHoecker]

When using Postman as your MCP client it sends cancellation notifications frequently whenever it encounters an issue. Clogging up the std out with unhelpful error messages

ERROR io.modelcontextprotocol.spec.McpServerSession [http-nio-8080-exec-9] No handler registered for notification method: notifications/cancelled

[He-Pin]

@tzolov Will this be supported in 0.12.0?

[yzaparto]

@chemicL @tzolov I can start looking into this.

[yzaparto]

@chemicL @tzolov I took a stab at it here: #803