/// Represents a complete SMTP response (possibly multi-line).
/// SMTP responses consist of a 3-digit code and one or more text lines.
public struct SMTPResponse: Sendable {
	public let code: Int
	public let lines: [String]

	public var message: String {
		lines.joined(separator: "\n")
	}

	public var isSuccess: Bool {
		code >= 200 && code < 400
	}
}
