public boolean warmUpStorage(final Address address, final Bytes32 slot) {
    return txValues.warmedUpStorage().put(address, slot, Boolean.TRUE) != null;
  }
"Warms up" the storage slot as per EIP-2929

@param address the address whose storage is being warmed up
@param slot the slot being warmed up
@return true if the storage slot was already warmed up
evm/src/main/java/org/hyperledger/besu/evm/frame/MessageFrame.java