Add a test for ensuring that a peer can download all valid TXs when
faced with two peers with conflicting tx order.

Replace the central decsision thread by having server threads coordinate
between them by blocking on STM actions.

Use sharedGeneration to track if the sharedState really changed and only
write to the tvar if it changed.

This makes common operations like receiving and acking a txid that is
already retained something that only affects the peer local state.

Remove shared states that where only written to.

Have the peer update its score during phase change. This makes State's
idle calculation quicker since peers will drain back to 0.

Mark pacIdlePeerScores as lazy to avoid doing the calculations when it
isn't needed.

Add benchmarks for V2

Instead of traversing all peers only touch the peers that need to wake
up.

Avoid copying the map when encountering an existing advertiser.

We don't need to track the ack state, it can be derived by the time we
decide to ack a TX. So txAdvertisers can just be a Set member check.

Remove the tracking of advertisers in TxEntry.
This change also changing how scoring is used to rank peers.
A peers score affects how long time after the TX owners lease expire
they can wake up and attempt to claim it. This means that
acknowledgement/downloading requires minimal coordination between peers.

The first peer that advertised a new txid always got a lease on it.
This is a problem since the peer may be at capacity and unable to
request the TX.
Update the behaviour so that anyone peer that advertise a txid can gain
the first claim.

Replace the local state tvar with V1's Stateful types.

Improve comment around deletion of retaind txs.

The retained functions in Types.hs are just small wrappes around IntPSQ
functions.

Use nothunks to assert that there are no thunks after some property
based tests.

If there is at least one TX outstanding don't ack the final txid in the
window

We don't track peers that don't have an ongoing attempt any longer so
TxNoAttempt isn't needed.

Not only idle peers but all peers should be notified when something
changes for one of their TX.s

When picking TXs to submit to the mempool stop at gaps.
When picking TXs to download use the peer's advertisement order as a
guide, not the TxKey order.

Test the peer score functionality.
Use arbitrary TxDecisionPolicy instead of the defaultTxDecisionPolicy.

Add tests that verify that V2 is robust even if peers are late or omit
TXs in replies.

Add prop_txSubmission_score_impairment which verifies TX submisssion
V2's scoring functionality.

Test nextPeerAction but running it through a series of triggers for a
small group of peers.

checkNoThunks was always true, unsafeNoThunks wasn't really called.
seq forces val to WHNF, but deeper thunks will be detected.

With no-thunk checks in prop_nextPeerAction_processesAllTriggers the
prop_nextPeerAction_prioritisesSubmit isn't needed.

Convert trivial nextPeerAction_claimsRejectedTxFromOtherAdvertiser
to a unit tests.

Fold prop_nextPeerAction_claimsExpiredLease into
prop_nextPeerAction_claimsClaimableTx which is expanded
to cover both case which is expanded
to cover both casess

Convert the direct server benchmark into one that can run multiple peers
with async.

Avoid Double conversions, similar to muxs diffTimeToMicroseconds.

Use IntSet for faster lookups for retained keys.
IntPSQ is still needed for quick removal of expeired entries.

Reduce STM contention in V2 TxSubmission inbound by splitting per-peer
in-flight bookkeeping out of SharedTxState into a small per-peer
PeerTxInFlight TVar. SharedTxState is now only written when the shared
state updates. The common case of a new peer advertising an existing
txid is just a read operation for the shared state and a write operation
into the peer local TVar.

Break out mempoolGetSnapshot into its own atomic transaction.

Add the conter thread to the test cases.
Add meta tests for AppV2 generators/shrinkers