Converts Data objects to hex strings

dataToHex.swift

extension Data {
    var hexString: String {
        return withUnsafeBytes { (b: UnsafePointer<UInt8>) -> String in
            var output = ""
            let end = b.advanced(by: count)
            var ptr = b
            while ptr < end {
                let value = ptr[0]
                output += String(format: "%02X", arguments: [value])
                ptr = ptr.advanced(by: 1)
            }
            return output
        }
    }   
}