Whether an SSE upgrade was refused for this request because the client's Accept provably excludes text/event-stream. The transport surfaces this as a 406 Not Acceptable after dispatch (see streamable_http.handlePost).
Whether an SSE upgrade was refused for this request because the client's Accept provably excludes text/event-stream. The transport surfaces this as a 406 Not Acceptable after dispatch (see streamable_http.handlePost).