Maps each spent outpoint to the in-mempool transaction that spends it.
Declared in <txmempool.h>
[[guarded_by(0x7fd7537b8e68), guarded_by(0x7fd74eec57f8), guarded_by(0x7fd75e706e48), guarded_by(0x7fd759893618), guarded_by(0x7fd75ce055e8), guarded_by(0x7fd759f6ea78), guarded_by(0x7fd75b82ecb8), guarded_by(0x7fd73e8acf18)]]
indirectmap<COutPoint, txiter> mapNextTx;