TODO: overview of writing custom integrations
116.1 Writing Custom Route Predicate Factories
TODO: document writing Custom Route Predicate Factories
116.2 Writing Custom GatewayFilter Factories
TODO: document writing Custom GatewayFilter Factories
116.3 Writing Custom Global Filters
TODO: document writing Custom Global Filters
116.4 Writing Custom Route Locators and Writers
TODO: document writing Custom Route Locators and Writers