OptionaldestinationsPrimary routing destinations. At most 10 are allowed. At least one is
required on Create. On Update, provide this list when replacing the full
config or updating config.routing.destinations; other granular routing
updates do not require resending destinations. The intermediate
config.routing mask path is not supported.
OptionalfallbackFallback routing applied after a primary destination fails. Fallback destinations are tried in the listed order.
Routing configuration for a model service, nesting destinations and fallback under a single sub-message.