Per-script breakdown
* @param arr 数组
，更多细节参见爱思助手下载最新版本
Web streams use a locking model to prevent multiple consumers from interleaving reads. When you call getReader(), the stream becomes locked. While locked, nothing else can read from the stream directly, pipe it, or even cancel it — only the code that is actually holding the reader can.
Anthony Lewis,Local Democracy Reporting Service