code: public Observable<Boolean> deleteConversation(String conversationId) {
  
          return asObservable(new Executor<Boolean>() {
              @Override
              void execute(ChatStore store, Emitter<Boolean> emitter) {
                  store.beginTransaction();
                  boolean isSuccess = store.deleteConversation(conversationId);
                  store.endTransaction();
                  emitter.onNext(isSuccess);
                  emitter.onCompleted();
              }
          });
      }
docs: Delete conversation from the store.
  
  @param conversationId Unique conversation id.
  @return Observable emitting result.