Swift 2.3
let dataArray: [UInt8] = Array(UnsafeBufferPointer
(start: UnsafePointer<UInt8>(data.bytes),
count: data.length))
Swift 3
let data = "foo".data(using: .utf8)!
let array = data.withUnsafeBytes {
[UInt8](UnsafeBufferPointer(start: $0, count: data.count))
}
