- make `logging.GetLogger(ctx, Subsys)` the authoritative `logger.Logger` factory function
- the context carries a linked list of injected fields which
`logging.GetLogger` adds to the logger it returns
- introduce the concept of tasks and spans, also tracked as linked list within ctx
- [ ] TODO automatic logging of span begins and ends, with a unique
ID stack that makes it easy to follow a series of log entries in
concurrent code
- ability to produce a chrome://tracing-compatible trace file,
either via an env variable or a `zrepl pprof` subcommand
- this is not a CPU profile, we already have go pprof for that
- but it is very useful to visually inspect where the
replication / snapshotter / pruner spends its time
( fixes#307 )
- prior to this patch, context cancellation would leave rpc.Server open
- did not make problems because context was only cancelled by SIGINT,
which was immediately followed by os.Exit
treat handshake errors as permanent on the client
The issue was observed by 100% CPU usage due to lack ofrate-limiting in
dataconn.ReqPing retries=> safeguard that
