code: public Observable<ComapiResult<Void>> isTyping(@NonNull final String conversationId) {
  
          final String token = getToken();
  
          if (sessionController.isCreatingSession() || TextUtils.isEmpty(token)) {
              return Observable.error(getSessionStateErrorDescription());
          } else {
              return doIsTyping(token, conversationId, true);
          }
      }
docs: Send 'user is typing'.
  
  @param conversationId ID of a conversation.
  @return Observable to send event.