private synchronized <T> @NonNull Collection<@NonNull ParameterInjector<C, ?>> injectors(final @NonNull TypeToken<T> type) {
        return Collections.unmodifiableCollection(this.injectors.stream()
                .filter(pair -> pair.first().test(type))
                .map(Pair::second)
                .collect(Collectors.toList()));
    }
Registers an injection service that will be able to provide injections using
{@link #getInjectable(Class, CommandContext, AnnotationAccessor)}.

@param service Service implementation
@return {@code this}
cloud-core/src/main/java/org/incendo/cloud/injection/ParameterInjectorRegistry.java