隐者艾伦的技术博客
从github上面下载MixedRealityToolkit-Unity-main案例库，然后试着通过unity打开，报错：
Assets\Data Binding Example\Scripts\DataSourceReflectionListTest.cs(63,17): error CS0246: The type or namespace name ‘DataSourceReflection’ could not be found (are you missing a using directive or an assembly reference?)
unity打开报错，包括不限于：Library\PackageCache\com.microsoft.mixedreality.toolkit.foundation@f2323a9b7aec\SDK\Experimental\NonNativeKeyboard\Scripts\CapsLockHighlight.cs(24,17): error CS0246: The type or namespace name ‘NonNativeKeyboard’ could not be found (are you missing a using directive or an assembly reference?)
unity打包报错，目标文件夹是空的，报错代码如下：
InvalidOperationException: Certificate Assets\WSATestCertificate.pfx is expired and cannot be used for a UWP build. To fix this, either delete it or select a different certificate in the player settings.
PostProcessWinRT.CreateTestCertificate () (at C:/buildslave/unity/build/PlatformDependent/MetroPlayer/Extensions/Managed/PostProcessWinRT.cs:1078)
PostProcessWinRT.Process () (at C:/buildslave/unity/build/PlatformDependent/MetroPlayer/Extensions/Managed/PostProcessWinRT.cs:168)
UnityEditor.UWP.BuildPostprocessor.PostProcess (UnityEditor.Modules.BuildPostProcessArgs args) (at C:/buildslave/unity/build/PlatformDependent/MetroPlayer/Extensions/Managed/ExtensionModule.cs:86)
Rethrow as BuildFailedException: Exception of type ‘UnityEditor.Build.BuildFailedException’ was thrown.
分析以后应该是这个项目的WSA证书过期了。解决办法：
众所周知原版hololens是没有5G模块的，它使用的芯片是高通骁龙850，高通骁龙850实际上是不具备5G基带的，当年也需要外挂X50基带才可以实现5G，更别说hololens2设计的时候可能原生就没有5G基带。后面有说要推出5G版本hololens，但最后还是鸽没了。
所以Hololens2如果想要实现户外功能就必须要自己加装5G模块，
于是博主斥巨资购入ZTE中兴 F50 5G上网模块（399元），这个好处是可以插入自己的5G SIM卡，切换自由。这款5G module的USB接口是typec usb3.0的，配合USB3.0+的数据线可以实现3750mb/s的数据传输，也就是3.7G左右的接口传输速率。
There might be a better way, but so far I’ve found that you can do this, and you can try other ways.
Goal: In UNITY, after clicking a button, three screens (or Raw images) appear in sequence: the first screen appears 1 second later, the second screen appears 3 seconds later and the first screen disappears, and the third screen appears 3 seconds later and the second screen disappears. The first step is to create a C# script in Assets, let’s name it delaydisplay3, double-click visual studio to open the edit.