code: public Conversation begin() {
          if (!virgin) {
              throw new IllegalStateException("You can only start a virgin conversation!");
          }
  
          Extensions.get(context.getBot(), ConversationRegistry.class).registerConversation(this);
  
          if (!silent) {
              SendableMessage response = currentPrompt.promptMessage(context);
  
              if (response != null) {
                  sendMessage(response);
              }
          }
  
          return this;
      }
docs: Initiates the conversation with the first prompt, registers the conversation in the registry.
  
  @return The current conversation