Using QByteRef with an index pointing outside the valid range of a QByteArray
使用5.12.0时，没有报错，但是程序换到5.14.0就报错UsingQByteRefwithanindexpointingoutsidethevalidrangeofaQByteArray.Thecorrespondingbehaviorisdeprecated,andwillbechangedinafutureversionofQt.原因：并没有给QByteArray初始化或分配空间，然后就使