BREAKING(async): deprecate deferred() in favor of Promise.withResolvers()

async/deferred.ts

@@ -6,6 +6,8 @@
 // typescript produces broken code when targeting ES5 code.
 // See https://github.com/Microsoft/TypeScript/issues/15202
 // At the time of writing, the github issue is closed but the problem remains.
+
+/** @deprecated (will be removed in 0.209.0) Use {@linkcode Promise.withResolvers} instead. */
 export interface Deferred<T> extends Promise<T> {
   readonly state: "pending" | "fulfilled" | "rejected";
   resolve(value?: T | PromiseLike<T>): void;
@@ -14,6 +16,8 @@ export interface Deferred<T> extends Promise<T> {
 }
 
 /**
+ * @deprecated (will be removed in 0.209.0) Use {@linkcode Promise.withResolvers} instead.
+ *
  * Creates a Promise with the `reject` and `resolve` functions placed as methods
  * on the promise object itself.
  *