How do i convert HexString To ByteArray in Swift 3, Conversion of String to Data with nicer syntax.

func stringToBytes(_ string: String) -> [UInt8]? {
    let length = string.characters.count
    if length & 1 != 0 {
        return nil
    }
    var bytes = [UInt8]()
    bytes.reserveCapacity(length/2)
    var index = string.startIndex
    for _ in 0..<length/2 {
        let nextIndex = string.index(index, offsetBy: 2)
        if let b = UInt8(string[index..<nextIndex], radix: 16) {
            bytes.append(b)
        } else {
            return nil
        }
        index = nextIndex
    }
    return bytes
}

let bytes = stringToBytes("7661706f72")
print(String(bytes: bytes!, encoding: .utf8)) //->Optional("vapor")

static func hexStringToData(string: String) -> Data {
    let stringArray = Array(string)
    var data: Data = Data()
    for i in stride(from: 0, to: string.count, by: 2) {
        let pair: String = String(stringArray[i]) + String(stringArray[i+1])
        if let byteNum = UInt8(pair, radix: 16) {
            let byte = Data([byteNum])
            data.append(byte)
        }
        else{
            fatalError()
        }
    }
    return data
}