This PR will allow a previously underpriced transaction back in after a timeout
of 5 minutes. This will block most transaction spam but allow for transactions to
be re-broadcasted on networks with less transaction flow.
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Co-authored-by: Felix Lange <fjl@twurst.com>
# Conflicts:
# eth/fetcher/tx_fetcher.go
* all: move main transaction pool into a subpool
* go.mod: remove superfluous updates
* core/txpool: review fixes, handle txs rejected by all subpools
* core/txpool: typos
