Swift 4 Any to Bytes (and back again) conversion (Foundationless! No Data or NSData!)

main.swift

// Notice no Foundation :3

typealias Byte = UInt8
typealias Bytes = [Byte]

func getBytes<Input>(_ input: Input) -> Bytes {
    return withUnsafeBytes(of: input) { Bytes($0) }
}

// You must be ABSOLUTELY SURE about input bytes, or enjoy your fresh and crispy BAD_ACCESS runtime error
// So obviously, this is very unsafe if you don't know what you're doing.
// But if you came here, you most probably know what you're doing :)
// Obviously, precondition stops working when you're dealing with non-trivial types (why would you?)
func cast<Result>(_ input: Bytes) -> Result {
    precondition(
        MemoryLayout<Result>.size == input.count,
        "Memory layout size for result type '\(Result.self)' (\(MemoryLayout<Result>.size) bytes) does not match with given byte array length (\(input.count) bytes)"
    )
    return input.withUnsafeBytes {
        $0.baseAddress!.assumingMemoryBound(to: Result.self).pointee
    }
}