/** 把 ReadableStream 转换为 Blob  */
export async function readableStreamToBlob(stream: ReadableStream): Promise<Blob> {
    const reader = stream.getReader()
    const chunks = []
    while (true) {
        const { done, value } = await reader.read()
        if (done) {
            break
        }
        chunks.push(value)
    }
    return new Blob(chunks)
}