Fixing type problem on AsyncIter

src/asynciter.ts

@@ -39,7 +39,7 @@ export default class AsyncIteratorFromCB<T> implements AsyncIterable<T> {
       this.#onClose.forEach((cb) => cb());
    }
 
-   [Symbol.asyncIterator]() {
+   [Symbol.asyncIterator](): AsyncIterator<T, undefined, any> {
       const queue: IAsyncIteratorMessage<T>[] = [];
       const signal = new Signal();
       this.#onData.subscribe((data) => {