https://stackoverflow.com/q/58369930/1271826

Iso8601.swift

// Personally, I would have done this on `DateFormatter` extension, but 
// did it on Formatter so it would work with provided code snippet.

extension Formatter {
    static var iso8601: DateFormatter = {
        let formatter = DateFormatter()
        formatter.locale = Locale(identifier: "en_US_POSIX")
        formatter.timeZone = TimeZone(secondsFromGMT: 0)
        formatter.dateFormat = "yyyy-MM-dd'T'HH:mm:ss.SSSSSS"
        return formatter
    }()
}