public void writeTo(final RLPOutput out) {
    out.startList();

    out.writeBytes(blockHash);
    out.writeIntScalar(transactionIndex);

    out.endList();
  }
Specifies the location of a transaction within the blockchain (where the transaction was included
in the block and location within this block's transactions list).
ethereum/core/src/main/java/org/hyperledger/besu/ethereum/chain/TransactionLocation.java