Swift Convert URLRequest to curl command

Extensions+URLRequest.swift

extension URLRequest {
    func toCurlCommand() -> String {
        func escapeTerminalString(_ value: String) -> String {
            return value.replacingOccurrences(of: "\"", with: "\\\"", options:[], range: nil)
        }
        
        let method = self.httpMethod ?? "GET"
        var returnValue = "curl -i \n    -X \(method) "
        
        for (key, value) in self.allHTTPHeaderFields ?? [:] {
            let escapedKey = escapeTerminalString(key)
            let escapedValue = escapeTerminalString(value)
            returnValue += "\n    -H \"\(escapedKey): \(escapedValue)\" "
        }
        
        if let httpBody = self.httpBody, self.httpMethod == "POST" {
            let maybeBody = String(data: httpBody, encoding: String.Encoding.utf8)
            if let body = maybeBody {
                returnValue += "\n    -d \"\(escapeTerminalString(body))\" "
            }
        }
        
        let URLString = self.url?.absoluteString ?? "<unknown url>"
        returnValue += "\n    \"\(escapeTerminalString(URLString))\""
        return returnValue.replacingOccurrences(of: "\n", with: "\\\n")
    }
}