code: func newRPCRawTransactionFromBlockIndex(b *types.Block, index uint64) hexutil.Bytes {
  	txs := b.Transactions()
  	if index >= uint64(len(txs)) {
  		return nil
  	}
  	blob, _ := rlp.EncodeToBytes(txs[index])
  	return blob
  }
docs: // newRPCRawTransactionFromBlockIndex returns the bytes of a transaction given a block and a transaction index.