String+hexRepresentation.swift

private func _hexString<I: BinaryInteger>(_ value: I) -> String {
    "0x" + String(value, radix: 16)
}

extension Character {
    func hexRepresentation() -> String {
        unicodeScalars
            .map { _hexString($0.value) }
            .joined(separator: ", ")
    }
}

extension StringProtocol {
    func hexRepresentation() -> String {
        unicodeScalars
            .map { _hexString($0.value) }
            .joined(separator: ", ")
    }
}