docs: public final void close() {
          synchronized (this.lock) {
              final SessionState oldState = this.state;
  
              switch (this.state) {
                  case CREATED:
                  case OPENING:
                      this.state = SessionState.CLOSED_LOGIN_FAILED;
                      postStateChange(oldState, this.state, new FacebookException(
                              "Log in attempt aborted."));
                      break;
  
                  case CREATED_TOKEN_LOADED:
                  case OPENED:
                  case OPENED_TOKEN_UPDATED:
                      this.state = SessionState.CLOSED;
                      postStateChange(oldState, this.state, null);
                      break;
  
                  case CLOSED:
                  case CLOSED_LOGIN_FAILED:
                      break;
              }
          }
      }