bitswap/client: add option to disable duplicated block stats

[hsanjuan]

Keeping a counter should not require query-ing the blockstore repeteadly for every single block received, so I have added an option to disable it.

Currently there is the assumption that doing Has() calls is cheap. That can be correct for most cases but also badly incorrect for others.

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[codecov]

Codecov Report

Merging #195 (3c22aeb) into main (38b183c) will increase coverage by 0.00%.
The diff coverage is 55.55%.

@@           Coverage Diff           @@
##             main     #195   +/-   ##
=======================================
  Coverage   65.65%   65.66%           
=======================================
  Files         207      207           
  Lines       25135    25141    +6     
=======================================
+ Hits        16503    16508    +5     
- Misses       7165     7169    +4     
+ Partials     1467     1464    -3     

Files	Coverage Δ
bitswap/client/client.go	90.42% <55.55%> (+1.00%)	⬆️

... and 13 files with indirect coverage changes

[Jorropo]

I don't think anyone is using this to compare against the actual blockstore, I think it's more meant when you download the same block from multiple nodes.
There an in memory LRU or refactoring this to compare against our wantlist (if we get a block that isn't in our wantlist anymore we can assume it may be a duplicate). Would solve the same thing.

[hsanjuan]

I am not sure what this stat is being used for or why it is implemented like this, I just want the ability to disable it.

[aschmahmann]

@Jorropo any objection to merging this?

[hacdias]

Ping @Jorropo

[Jorropo]

That fine, it solves the problem and allows to optin.

[Jorropo]

@hsanjuan sorry for the delay, this code is good and doesn't make anything worst even if it could be optimized.
Could you please add a changelog entry ?

[hsanjuan]

@Jorropo now without allocating an empty slice

[Jorropo]

LGTM

[Jorropo]

A test would be good to catch regressions but I think this is fine.

[hsanjuan]

Merge and will do a follow up with a test some day. 👀