docs: public boolean delete(final Txn<T> txn, final T key, final T val) {
      if (SHOULD_CHECK) {
        requireNonNull(txn);
        requireNonNull(key);
        txn.checkReady();
        txn.checkWritesAllowed();
      }
  
      txn.kv().keyIn(key);
  
      Pointer data = null;
      if (val != null) {
        txn.kv().valIn(val);
        data = txn.kv().pointerVal();
      }
      final int rc = LIB.mdb_del(txn.pointer(), ptr, txn.kv().pointerKey(), data);
      if (rc == MDB_NOTFOUND) {
        return false;
      }
      checkRc(rc);
      return true;
    }