Discord4J: No instance(s) of type variable(s) R exist so that void conforms to Mono<? extends R>
问题 I have the following error no instance(s) of type variable(s) R exist so that void conforms to Mono<? extends R> . How would I resolve this? Im writing a discord bot in java with Discord4J. When a user reacts to the bot emoji for the corresponding gender id like to write to the database (or in this example simply print) the user and their gender. I have a database method: public static void setUserGender(String u, ReactionEmoji e){ String gender = (e.equals(EmojiUtils.EMOJI_MALE)) ? "male" :