goroutine leak when test with tikv

goleak: Errors on successful test run: found unexpected goroutines:
[Goroutine 4400 in state select, with github.com/tikv/client-go/v2/internal/retry.newBackoffFn.func1 on top of the stack:
goroutine 4400 [select]:
github.com/tikv/client-go/v2/internal/retry.newBackoffFn.func1(0x1fce648, 0xc0000c6010, 0xffffffffffffffff, 0x5)
	/home/runner/work/client-go/client-go/internal/retry/config.go:181 +0x452
github.com/tikv/client-go/v2/internal/retry.(*Backoffer).BackoffWithCfgAndMaxSleep(0xc001bee870, 0xc0004a89f0, 0xffffffffffffffff, 0x1f9edc0, 0xc000e1ad20, 0xc000d94ea8, 0x4103f8)
	/home/runner/work/client-go/client-go/internal/retry/backoff.go:170 +0x9f3
github.com/tikv/client-go/v2/internal/retry.(*Backoffer).Backoff(0xc001bee870, 0xc0004a89f0, 0x1f9edc0, 0xc000e1ad20, 0x0, 0x0)
	/home/runner/work/client-go/client-go/internal/retry/backoff.go:120 +0xd8
github.com/tikv/client-go/v2/internal/locate.(*RegionCache).loadRegion(0xc00032f600, 0xc001bee870, 0xc001b33a32, 0x2, 0x2, 0x0, 0x0, 0x0, 0x0)
	/home/runner/work/client-go/client-go/internal/locate/region_cache.go:1314 +0x871
github.com/tikv/client-go/v2/internal/locate.(*RegionCache).findRegionByKey(0xc00032f600, 0xc001bee870, 0xc001b33a32, 0x2, 0x2, 0x1be3c00, 0x1c749c0, 0x1d2817b, 0xd)
	/home/runner/work/client-go/client-go/internal/locate/region_cache.go:819 +0x5f7
github.com/tikv/client-go/v2/internal/locate.(*RegionCache).LocateKey(0xc00032f600, 0xc001bee870, 0xc001b33a32, 0x2, 0x2, 0xc000d953e8, 0xc000d95398, 0x8b30f0)
	/home/runner/work/client-go/client-go/internal/locate/region_cache.go:788 +0x79
github.com/tikv/client-go/v2/txnkv/transaction.groupSortedMutationsByRegion(0xc00032f600, 0xc001bee870, 0x1fe70b8, 0xc001cbe9c0, 0xb, 0x0, 0x0, 0x0, 0x0)
	/home/runner/work/client-go/client-go/txnkv/transaction/2pc.go:765 +0x145
github.com/tikv/client-go/v2/txnkv/transaction.(*twoPhaseCommitter).groupMutations(0xc000e34600, 0xc001bee870, 0x1fe70b8, 0xc001cbe9c0, 0x4103f8, 0x18, 0x1b24a80, 0x0, 0x0)
	/home/runner/work/client-go/client-go/txnkv/transaction/2pc.go:782 +0x85
github.com/tikv/client-go/v2/txnkv/transaction.(*twoPhaseCommitter).doActionOnMutations(0xc000e34600, 0xc001bee870, 0x1fc95b0, 0x350ec70, 0x1fe70b8, 0xc001cbe9c0, 0x0, 0x0)
	/home/runner/work/client-go/client-go/txnkv/transaction/2pc.go:731 +0x75
github.com/tikv/client-go/v2/txnkv/transaction.(*twoPhaseCommitter).pessimisticRollbackMutations(...)
	/home/runner/work/client-go/client-go/txnkv/transaction/pessimistic.go:319
github.com/tikv/client-go/v2/txnkv/transaction.actionPessimisticRollback.handleSingleBatch(0xc000e34600, 0xc001bee870, 0x2, 0x1, 0x1, 0x1fe70b8, 0xc001cbe9c0, 0x1, 0xd9ed48, 0x0)
	/home/runner/work/client-go/client-go/txnkv/transaction/pessimistic.go:289 +0x308
github.com/tikv/client-go/v2/txnkv/transaction.(*twoPhaseCommitter).doActionOnBatches(0xc000e34600, 0xc001bee870, 0x1fc95b0, 0x350ec70, 0xc001cbc750, 0x1, 0x1, 0x4000, 0x7f0e6a7a45b8)
	/home/runner/work/client-go/client-go/txnkv/transaction/2pc.go:982 +0xfc
github.com/tikv/client-go/v2/txnkv/transaction.(*twoPhaseCommitter).doActionOnGroupMutations(0xc000e34600, 0xc001bee870, 0x1fc95b0, 0x350ec70, 0xc001cbc720, 0x1, 0x1, 0x0, 0x0)
	/home/runner/work/client-go/client-go/txnkv/transaction/2pc.go:963 +0xb19
github.com/tikv/client-go/v2/txnkv/transaction.(*twoPhaseCommitter).doActionOnMutations(0xc000e34600, 0xc001bee870, 0x1fc95b0, 0x350ec70, 0x1fe70b8, 0xc001cbe900, 0x29, 0x9)
	/home/runner/work/client-go/client-go/txnkv/transaction/2pc.go:740 +0xf6
github.com/tikv/client-go/v2/txnkv/transaction.(*twoPhaseCommitter).pessimisticRollbackMutations(...)
	/home/runner/work/client-go/client-go/txnkv/transaction/pessimistic.go:319
github.com/tikv/client-go/v2/txnkv/transaction.(*KVTxn).asyncPessimisticRollback.func1(0x1fce648, 0xc0000c6010, 0xc001bdab40, 0xc001bff0b0, 0xc000e34600, 0xc001b43470, 0x1, 0x1)
	/home/runner/work/client-go/client-go/txnkv/transaction/txn.go:796 +0x1bf
created by github.com/tikv/client-go/v2/txnkv/transaction.(*KVTxn).asyncPessimisticRollback
	/home/runner/work/client-go/client-go/txnkv/transaction/txn.go:779 +0x159

Start with txnkv/transaction/txn.go around asyncPessimisticRollback and follow the stack through pessimistic.go, 2pc.go, locate/region_cache.go, and internal/retry/config.go. Reproduce the successful test run with goleak and inspect whether the goroutine remains after the test completes. Done means the reported unexpected goroutine no longer appears.