void put(final int item) {
    if (!marked[item]) {
      listEnd++;
      items[listEnd] = item;
      marked[item] = true;
    }
  }
Put an item in the work list. This is idempotent, an item will only be added on the first call.

@param item the item to add to the list.
evm/src/main/java/org/hyperledger/besu/evm/code/WorkList.java