let data = Data()
let digest = data.md5
print("md5: \(digest)")

// prints: "md5: d41d8cd98f00b204e9800998ecf8427e"

let input = "The quick brown fox jumps over the lazy dog"
let digest = input.utf8.md5
print("md5: \(digest)")

// prints: "md5: 9e107d9d372bb6826bd81d3542a419d6"

let appID = try! Data(contentsOf: Bundle.main.executableURL!).md5
// can be used to send a unique id of the app version to a server or so.

/// Represents a 16 byte digest value, created from hashing arbitrary data.
public struct MD5Digest : Hashable, RawRepresentable, CustomStringConvertible, Codable {

    /// Perform hashing of the supplied data.
    public init(from input: Data)

    /// Create a digest from reading a hex representation from the supplied string.
    public init?(rawValue: String)

    /// The 32 digit hex representation.
    public var rawValue: String { get }

    /// The 32 digit hex representation.
    public var description: String { get }

    /// The raw bytes of the digest value, always exactly 16 bytes.
    public var data: Data { get }

    /// The raw bytes of the digest value as a tuple.
    public var bytes: (UInt8, UInt8, UInt8, UInt8, UInt8, UInt8, UInt8, UInt8, UInt8, UInt8, UInt8, UInt8, UInt8, UInt8, UInt8, UInt8) { get }
}


public extension Data {

    /// Computes md5 digest value of the contained bytes.
    public var md5: MD5Digest { get }
}

public extension String.UTF8View {

    /// Computes md5 digest value of the string's UTF-8 representation.
    public var md5: MD5Digest { get }
}