return spec;
        };
        return doRegisterIfAbsent(name, uncheckedNonnullCast(implementationType), uncheckedNonnullCast(buildServiceSpecSupplier));
    }

    private <T extends BuildService<P>, P extends BuildServiceParameters> BuildServiceProvider<T, P> doRegisterIfAbsent(String name, Class<T> implementationType, Supplier<BuildServiceSpec<P>> specSupplier) {