details:
* Tested features
+ Successively store filters with increasing filter ID (think block number)
+ Cascading through fifos, deeper fifos merge groups of filters
+ Fetch squash merged N top fifos
+ Delete N top fifos, push back merged fifo, continue storing
+ Fifo chain is verified by hashes and filter ID
* Not tested yet
+ Real live scenario (using data dumps)
+ Real filter data (only shallow filters used so far)
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