public EurekaEndpointGroupBuilder instanceId(String instanceId) {
        requireNonNull(instanceId, "instanceId");
        checkArgument(!instanceId.isEmpty(), "instanceId is empty.");
        checkState(vipAddress == null && secureVipAddress == null,
                   "cannot set instanceId with the %s.",
                   vipAddress != null ? "vipAddress" : "secureVipAddress");
        this.instanceId = instanceId;
        return this;
    }
Sets the specified {@code instanceId}. {@link EurekaEndpointGroup} will only retrieve the registry
information whose instance ID is the specified {@code instanceId}.

@throws IllegalStateException if {@link #vipAddress(String)} or {@link #secureVipAddress(String)} is
                              called already
eureka/src/main/java/com/linecorp/armeria/client/eureka/EurekaEndpointGroupBuilder.java