@Override
        public void onMessage(@Nonnull ChannelAgent<R> agent, @Nonnull R message) {
            SimpleConversationChannel.this.replyListeners.get(message.getConversationId()).removeIf(l -> l.onReply(message));
        }
Simple implementation of {@link ConversationChannel}.

@param <T> the outgoing message type
@param <R> the reply message type
helper/src/main/java/me/lucko/helper/messaging/conversation/SimpleConversationChannel.java