addOutgoingServer method
Implementation
void addOutgoingServer(ServerConfig server) {
outgoingServers ??= <ServerConfig>[];
outgoingServers!.add(server);
preferredOutgoingServer ??= server;
if (server.type == ServerType.smtp && preferredOutgoingSmtpServer == null) {
preferredOutgoingSmtpServer = server;
}
}