code: @Setup(Level.Trial)
    public void setup() throws Exception {
      registry = new MutableHandlerRegistry();
      fullMethodNames = new ArrayList<>(serviceCount * methodCountPerService);
      for (int serviceIndex = 0; serviceIndex < serviceCount; ++serviceIndex) {
        String serviceName = randomString();
        ServerServiceDefinition.Builder serviceBuilder = ServerServiceDefinition.builder(serviceName);
        for (int methodIndex = 0; methodIndex < methodCountPerService; ++methodIndex) {
          String methodName = randomString();
  
          MethodDescriptor<Void, Void> methodDescriptor = MethodDescriptor.<Void, Void>newBuilder()
              .setType(MethodDescriptor.MethodType.UNKNOWN)
              .setFullMethodName(MethodDescriptor.generateFullMethodName(serviceName, methodName))
              .setRequestMarshaller(TestMethodDescriptors.voidMarshaller())
              .setResponseMarshaller(TestMethodDescriptors.voidMarshaller())
              .build();
          serviceBuilder.addMethod(methodDescriptor,
              new ServerCallHandler<Void, Void>() {
                @Override
                public Listener<Void> startCall(ServerCall<Void, Void> call,
                    Metadata headers) {
                  return null;
                }
              });
          fullMethodNames.add(methodDescriptor.getFullMethodName());
        }
        registry.addService(serviceBuilder.build());
      }
    }
docs: Set up the registry.