TODOs and FIXMEs

A grep -rE "TODO|FIXME|HACK" --include="*.go" over the source tree finds 441 occurrences across 196 files.

Distribution at a glance (by directory):

• server/etcdserver/ and below — the bulk of the comments, mostly TODOs around apply/raft pacing.
• server/storage/wal/ — small but pointed list (e.g. constants noted as // TODO: a better const? in server/etcdserver/raft.go).
• tests/ — TODOs about slow / flaky tests; many cross-reference open type/flake issues.

Examples

A representative selection (paths and approximate excerpts; grep for the surrounding context):

• server/etcdserver/raft.go — // TODO: a better const? next to maxInflightMsgs = 4096 / 8.
• server/storage/mvcc/kvstore_test.go — multiple TODOs about replacing test setup boilerplate.
• server/etcdserver/api/v3rpc/watch.go — TODOs noting suboptimal cancellation paths.
• server/etcdserver/apply/ — TODOs about consolidating the layered applier.
• tests/robustness/validate/ — TODOs covering not-yet-checked invariants.
• client/v3/retry.go — comments calling out the imperfect retry classification.

There is also a smaller crop of FIXME (30) and HACK (10) markers; the HACKs are mostly in test scaffolding, the FIXMEs in apply / mvcc.

Suggested approach

• Pick a directory, run grep -nE "TODO|FIXME|HACK" --include="*.go" -r <dir>, file an issue per non-trivial cluster, link the open type/flake issues already filed.
• The maintainers welcome cleanup PRs; per CONTRIBUTING.md, they prefer small focused PRs over giant sweeps.