@UnstableApi
    protected final void failInit(Throwable cause) {
        requireNonNull(cause, "cause");
        initialEndpointsFuture.completeExceptionally(cause);
    }
Fails the initialization of this {@link DynamicEndpointGroup} with the specified {@link Throwable}.
core/src/main/java/com/linecorp/armeria/client/endpoint/DynamicEndpointGroup.java