... unless they're UNCONDITIONAL_RELAY_DELAY old, or there has been
a response to a MEMPOOL request in the mean time.
This is accomplished using a rolling Bloom filter for the last
3500 announced transactions. The probability of seeing more than 100
broadcast events (which can be up to 35 txids each) in 2 minutes for
an outbound peer (where the average frequency is one per minute), is
less than 1 in a million.
This is a partial backport of [[https://github.com/bitcoin/bitcoin/pull/19109 | core#19109]] [3/5]
https://github.com/bitcoin/bitcoin/pull/19109/commits/43f02ccbff9b137d59458da7a8afdb0bf80e127f