fetch(Route one HTTP request:req):Promise<Response>
POST …/rpc/<method> dispatches an RPC, any
other GET opens an SSE stream, anything else is refused with 405.
Parameters
Returns
Promise<Response>
The SSE stream, the RPC answer, or an error response.
The Actor Entry
The actor’sfetch(req) entry calls it, from an override on the class. The HTTP Server shows the method.