使用https://www.npmjs.com/package/ngx-file-helpers
如何上传文件？
我正在尝试创建：
this.formData.append("file", this.picked['content'], this.picked["name"]);
选择public picked: ReadFile;
参见https://stackblitz.com/edit/receipt-admin?file=src%2Fapp%2Ffile-picker-demo%2Ffile-picker-demo.component.ts
但我得到：ERROR
Error: Failed to execute 'append' on 'FormData': parameter 2 is not of type 'Blob'.
如何将内容转换为Blob？