default boolean isEmpty() {
    return getNonce() == 0 && getBalance().isZero() && !hasCode();
  }
Whether the account is "empty".

<p>An account is defined as empty if:

<ul>
  <li>its nonce is 0;
  <li>its balance is 0;
  <li>its associated code is empty (the zero-length byte sequence).
</ul>

@return {@code true} if the account is empty with regard to the definition above, {@code false}
    otherwise.
evm/src/main/java/org/hyperledger/besu/evm/account/AccountState.java