Small tx response verification optimisation

[emhane]

Replaces Vec for HashSet in RequestTxHashes. This simplifies the look up of a hash from a PooledTransactions response in RequestHashes, which is done in verifying that hashes in the response were actually requested.

[mattsse]

all of this looks reasonable,

though one bad side-effect of this is that we now request hashes in random order, which can result in more work during pool import because we might need to reorder sequences from the same account that we request out of nonce order, assuming they are announced in order

wdyt @Rjected

[emhane]

all of this looks reasonable,

though one bad side-effect of this is that we now request hashes in random order, which can result in more work during pool import because we might need to reorder sequences from the same account that we request out of nonce order, assuming they are announced in order

wdyt @Rjected

random order already happens when the announcement is validated when data is put into hash map to dedup

[emhane]

all of this looks reasonable,
though one bad side-effect of this is that we now request hashes in random order, which can result in more work during pool import because we might need to reorder sequences from the same account that we request out of nonce order, assuming they are announced in order
wdyt @Rjected

random order already happens when the announcement is validated when data is put into hash map to dedup

if you think this is a problem now (if I remember correct you wished for the HashMap in dedup in validation), reminder to open an issue since is out of scope @mattsse