the vtable symbol may be undefined because the class is missing its key function

ld.lld: error: undefined symbol: vtable for Audio::AudioModule

>>> referenced by AudioModule.cpp:7 (AudioModule/src/AudioModule.cpp:7)

>>>               out/target/product/xxx/obj/SHARED_LIBRARIES/libaudiorouter_intermediates/AudioModule/src/AudioModule.o:(AudioModule::AudioModule(:AudioModule::ModuleType))

the vtable symbol may be undefined because the class is missing its key function (see https://lld.llvm.org/missingkeyfunction)

clang-9: error: linker command failed with exit code 1 (use -v to see invocation)

基類中的析構函數沒有定義導緻在派生類析構的時候虛函數表中找不到基類的析構函數的定義，進而導緻了連結出錯的問題。

實作父類中的析構函數即可解決問題

 ~AudioModule::AudioModule(){}