docs: @Override
    @Nullable
    public ServerMethodDefinition<?, ?> lookupMethod(String methodName, @Nullable String authority) {
      String serviceName = MethodDescriptor.extractFullServiceName(methodName);
      if (serviceName == null) {
        return null;
      }
      ServerServiceDefinition service = services.get(serviceName);
      if (service == null) {
        return null;
      }
      return service.getMethod(methodName);
    }