Converts the given source into an AsyncIterable object if it's not one already, returns null if failed.

If the given promise resolves to a ReadableStream<Uint8Array>, this function will return a new ReadableStream<Uint8Array> object that can be used to read the byte stream without the need to wait for the promise to resolve.

Wraps a source as an AsyncIterable object that can be used in the for await...of... loop for reading streaming data.