Type that forces a collection to not be empty

NonEmptyCollection.swift

public struct NonEmptyCollection<T: CollectionType> {

    let collection: T

    init?(collection: T) {
        if !collection.isEmpty {
            self.collection = collection
        } else {
            return nil
        }
    }
}

public extension NonEmptyCollection where T: ArrayLiteralConvertible {

    init(element: T.Element) {
        self.collection = T(arrayLiteral: element)
    }

}

/* 
Example Usage in API:

func receiveUpdates(NonEmptyCollection<[Update]>)
*/