// Get a message and write it to a file public static void writeToFile(IMessage message, string fileName) { // Create out generic class that holds any other classes GenericClass genericClass = new GenericClass { MyObject = Any.Pack(message) }; // Serialize the class and write it to a file using (Stream output = File.Open(fileName, FileMode.Append)) { MessageExtensions.WriteDelimitedTo(genericClass, output); } }