不过不知道对不对，最后log可能是太多一次性打印不出来，只能循环打印，readLen 长度为14866的转换后是uint8Array.length18645长度，试试上传华为云可不可以把

                  let buf = new ArrayBuffer(40960);// 500M

                  let readLen = fs.readSync(globalThis.fd, buf, { offset: 0 });
                 
                  fs.read(globalThis.fd, buf).then((readLen) => {

                    console.log(`readLen:${readLen}`);

                    let dataview = new DataView(buf)

                    let uint8Array = new Uint8Array(readLen);

                    for(var i =0;i<uint8Array.length;i++){
                      uint8Array[i]=dataview.getUint8(i)

                    }

                    let that = new util.Base64Helper();
                    let result1 = that.encodeToStringSync(uint8Array);

                    for(var i =0;i<result1.length;i++){
                      console.log(i+":"+result1[i])
                    }

                  })