message: CR: Use a fully optional verifiedToken
  Avoids generalizing behaviour of one *particular* server
  implementation to *all* server implementations.
diff: @@ -116,7 +116,7 @@ export interface ClientContext {
  }
  export interface ServerOnlyContext {
  - verifiedToken: object | undefined; // Set on server from JWT
  + verifiedToken?: object; // Set on server from JWT
  tags?: { [key: string]: string };
  logLevel?: string;
  logExtra?: { [key: string]: any };
  