TODO: overview of writing custom integrations
114.1 Writing Custom Route Predicate Factories
TODO: document writing Custom Route Predicate Factories
114.2 Writing Custom GatewayFilter Factories
TODO: document writing Custom GatewayFilter Factories
114.3 Writing Custom Global Filters
TODO: document writing Custom Global Filters
114.4 Writing Custom Route Locators and Writers
TODO: document writing Custom Route Locators and Writers