docs: @Override
      public final boolean complete(Object value) {
          for (; ; ) {
              final Object oldState = state;
              if (isDone(oldState)) {
                  warnIfSuspiciousDoubleCompletion(oldState, value);
                  return false;
              }
              if (compareAndSetState(oldState, value)) {
                  onComplete();
                  unblockAll(oldState, defaultExecutor);
                  return true;
              }
          }
      }