code: protected void instrumentNativeMethod(MutableClass mutableClass, MethodNode method) {
      method.access = method.access & ~Opcodes.ACC_NATIVE;
  
      RobolectricGeneratorAdapter generator = new RobolectricGeneratorAdapter(method);
      Type returnType = generator.getReturnType();
      generator.pushDefaultReturnValueToStack(returnType);
      generator.returnValue();
    }
docs: Creates native stub which returns the default return value.
  
  @param mutableClass Class to be instrumented
  @param method Method to be instrumented, must be native