ConfigurationClosure.swift

struct Manager {
	final class Configuration {
		var name: String = "default"
		var timeout: Double = 500
	}

	private let configuration: Configuration

	var name: String {
		return configuration.name
	}

	var timeout: Double {
		return configuration.timeout
	}

	init(configure: ((Configuration) -> Void)? = nil) {
		let configuration = Configuration()
		configure?(configuration)
		self.configuration = configuration
	}
}

let defaultManager = Manager()
defaultManager.name
defaultManager.timeout

let customManager = Manager {
	$0.name = "custom"
	$0.timeout = 2000
}
customManager.name
customManager.timeout