in memory store should set last saved date

[DavidBadura]

The InMemoryStore implementation of the Subscription Store never set the last saved date.

[github-actions]

Hello 👋

here is the most recent benchmark result:

SimpleSetupBench
================

+----------------------------------------+--------------------+--------------------+-----------+-----------------+------------+-------------+
|                                        | time (kde mode)                                     | memory                                     |
+----------------------------------------+--------------------+--------------------+-----------+-----------------+------------+-------------+
| subject                                | Tag: <current>     | Tag: base          | time-diff | Tag: <current>  | Tag: base  | memory-diff |
+----------------------------------------+--------------------+--------------------+-----------+-----------------+------------+-------------+
| benchLoad1Event ()                     | 951.800μs (±0.00%) | 996.200μs (±0.00%) | -4.46%    | 34.266mb        | 34.274mb   | -0.02%      |
| benchLoad10000Events ()                | 47.841ms (±0.00%)  | 49.993ms (±0.00%)  | -4.30%    | 34.266mb        | 34.274mb   | -0.02%      |
| benchSave1Event ()                     | 965.000μs (±0.00%) | 922.200μs (±0.00%) | +4.64%    | 33.765mb        | 33.765mb   | 0.00%       |
| benchSave10000Events ()                | 216.914ms (±0.00%) | 221.323ms (±0.00%) | -1.99%    | 33.765mb        | 33.765mb   | 0.00%       |
| benchSave10000Aggregates ()            | 7.260s (±0.00%)    | 7.642s (±0.00%)    | -5.00%    | 33.765mb        | 33.765mb   | 0.00%       |
| benchSave10000AggregatesTransaction () | 4.783s (±0.00%)    | 4.797s (±0.00%)    | -0.29%    | 33.765mb        | 33.765mb   | 0.00%       |
+----------------------------------------+--------------------+--------------------+-----------+-----------------+------------+-------------+

SnapshotsBench
==============

+----------------------------------------+--------------------+--------------------+-----------+-----------------+------------+-------------+
|                                        | time (kde mode)                                     | memory                                     |
+----------------------------------------+--------------------+--------------------+-----------+-----------------+------------+-------------+
| subject                                | Tag: <current>     | Tag: base          | time-diff | Tag: <current>  | Tag: base  | memory-diff |
+----------------------------------------+--------------------+--------------------+-----------+-----------------+------------+-------------+
| benchLoad10000EventsMissingSnapshot () | 47.402ms (±0.00%)  | 47.835ms (±0.00%)  | -0.91%    | 33.836mb        | 33.836mb   | 0.00%       |
| benchLoad10000Events ()                | 923.100μs (±0.00%) | 936.400μs (±0.00%) | -1.42%    | 33.836mb        | 33.836mb   | 0.00%       |
+----------------------------------------+--------------------+--------------------+-----------+-----------------+------------+-------------+

SubscriptionEngineBatchBench
============================

+---------------------------+-------------------+-------------------+-----------+-----------------+------------+-------------+
|                           | time (kde mode)                                   | memory                                     |
+---------------------------+-------------------+-------------------+-----------+-----------------+------------+-------------+
| subject                   | Tag: <current>    | Tag: base         | time-diff | Tag: <current>  | Tag: base  | memory-diff |
+---------------------------+-------------------+-------------------+-----------+-----------------+------------+-------------+
| benchHandle10000Events () | 72.027ms (±0.00%) | 72.575ms (±0.00%) | -0.76%    | 34.234mb        | 34.234mb   | 0.00%       |
+---------------------------+-------------------+-------------------+-----------+-----------------+------------+-------------+

SubscriptionEngineBench
=======================

+---------------------------+-----------------+-----------------+-----------+-----------------+------------+-------------+
|                           | time (kde mode)                               | memory                                     |
+---------------------------+-----------------+-----------------+-----------+-----------------+------------+-------------+
| subject                   | Tag: <current>  | Tag: base       | time-diff | Tag: <current>  | Tag: base  | memory-diff |
+---------------------------+-----------------+-----------------+-----------+-----------------+------------+-------------+
| benchHandle10000Events () | 3.167s (±0.00%) | 3.157s (±0.00%) | +0.30%    | 46.382mb        | 46.382mb   | 0.00%       |
+---------------------------+-----------------+-----------------+-----------+-----------------+------------+-------------+

PersonalDataBench
=================

+----------------------------------------+--------------------+--------------------+-----------+-----------------+------------+-------------+
|                                        | time (kde mode)                                     | memory                                     |
+----------------------------------------+--------------------+--------------------+-----------+-----------------+------------+-------------+
| subject                                | Tag: <current>     | Tag: base          | time-diff | Tag: <current>  | Tag: base  | memory-diff |
+----------------------------------------+--------------------+--------------------+-----------+-----------------+------------+-------------+
| benchLoad1Event ()                     | 906.900μs (±0.00%) | 910.900μs (±0.00%) | -0.44%    | 34.895mb        | 34.895mb   | 0.00%       |
| benchLoad10000Events ()                | 84.996ms (±0.00%)  | 82.623ms (±0.00%)  | +2.87%    | 34.895mb        | 34.895mb   | 0.00%       |
| benchSave1Event ()                     | 1.454ms (±0.00%)   | 1.493ms (±0.00%)   | -2.60%    | 34.895mb        | 34.895mb   | 0.00%       |
| benchSave10000Events ()                | 246.597ms (±0.00%) | 247.011ms (±0.00%) | -0.17%    | 34.897mb        | 34.897mb   | 0.00%       |
| benchSave10000Aggregates ()            | 11.457s (±0.00%)   | 11.383s (±0.00%)   | +0.65%    | 34.895mb        | 34.895mb   | 0.00%       |
| benchSave10000AggregatesTransaction () | 8.905s (±0.00%)    | 8.919s (±0.00%)    | -0.16%    | 35.396mb        | 35.396mb   | 0.00%       |
+----------------------------------------+--------------------+--------------------+-----------+-----------------+------------+-------------+

SimpleSetupStreamStoreBench
===========================

+----------------------------------------+--------------------+--------------------+-----------+-----------------+------------+-------------+
|                                        | time (kde mode)                                     | memory                                     |
+----------------------------------------+--------------------+--------------------+-----------+-----------------+------------+-------------+
| subject                                | Tag: <current>     | Tag: base          | time-diff | Tag: <current>  | Tag: base  | memory-diff |
+----------------------------------------+--------------------+--------------------+-----------+-----------------+------------+-------------+
| benchLoad1Event ()                     | 1.036ms (±0.00%)   | 1.034ms (±0.00%)   | +0.23%    | 34.862mb        | 34.862mb   | 0.00%       |
| benchLoad10000Events ()                | 57.541ms (±0.00%)  | 57.179ms (±0.00%)  | +0.63%    | 34.862mb        | 34.862mb   | 0.00%       |
| benchSave1Event ()                     | 1.013ms (±0.00%)   | 977.300μs (±0.00%) | +3.63%    | 34.862mb        | 34.862mb   | 0.00%       |
| benchSave10000Events ()                | 295.027ms (±0.00%) | 291.280ms (±0.00%) | +1.29%    | 34.862mb        | 34.862mb   | 0.00%       |
| benchSave10000Aggregates ()            | 7.548s (±0.00%)    | 7.530s (±0.00%)    | +0.24%    | 34.862mb        | 34.862mb   | 0.00%       |
| benchSave10000AggregatesTransaction () | 4.994s (±0.00%)    | 4.996s (±0.00%)    | -0.05%    | 34.862mb        | 34.862mb   | 0.00%       |
+----------------------------------------+--------------------+--------------------+-----------+-----------------+------------+-------------+

SplitStreamBench
================

+-------------------------+--------------------+--------------------+-----------+-----------------+------------+-------------+
|                         | time (kde mode)                                     | memory                                     |
+-------------------------+--------------------+--------------------+-----------+-----------------+------------+-------------+
| subject                 | Tag: <current>     | Tag: base          | time-diff | Tag: <current>  | Tag: base  | memory-diff |
+-------------------------+--------------------+--------------------+-----------+-----------------+------------+-------------+
| benchLoad10000Events () | 4.290ms (±0.00%)   | 4.261ms (±0.00%)   | +0.67%    | 37.072mb        | 37.072mb   | 0.00%       |
| benchSave10000Events () | 335.114ms (±0.00%) | 339.647ms (±0.00%) | -1.33%    | 37.145mb        | 37.145mb   | 0.00%       |
+-------------------------+--------------------+--------------------+-----------+-----------------+------------+-------------+

This comment gets update everytime a new commit comes in!