Boost multi-index container type storing mempool entries indexed by txid, wtxid, and entry time.
Declared in <txmempool.h>
using indexed_transaction_set = boost::multi_index_container<CTxMemPoolEntry, boost::multi_index::indexed_by<boost::multi_index::hashed_unique<mempoolentry_txid, SaltedTxidHasher>, boost::multi_index::hashed_unique<boost::multi_index::tag<index_by_wtxid>, mempoolentry_wtxid, SaltedWtxidHasher>, boost::multi_index::ordered_non_unique<boost::multi_index::tag<entry_time>, boost::multi_index::identity<CTxMemPoolEntry>, CompareTxMemPoolEntryByEntryTime>>>;