cmd/swarm/swarm-smoke: improve smoke tests (#1337)
swarm/network: remove dead code (#1339)
swarm/network: remove FetchStore and SyncChunkStore in favor of NetStore (#1342)
* swarm/network: propagate span with ctx
* swarm/network: try to stop stream.send.request spans on time
* swarm/storage: add chunk ref as a log to netstore.fetcher span
* swarm/newtork: WIP Span request span until delivery and put
* swarm/storage: Introduce new trace across single fetcher lifespan
* swarm/network: Put span ids for sendpriority in context value
* swarm: Add global span store in tracing
* swarm/tracing: Add context key constants
* swarm/tracing: Add comments
* swarm/storage: Remove redundant fix for filestore
* swarm/tracing: Elaborate constants comments
* swarm/network, swarm/storage, swarm:tracing: Minor cleanup
* swarm/network/stream: disambiguate chunk delivery messages (retrieval vs syncing)
* swarm/network/stream: addressed PR comments
* swarm/network/stream: stream protocol version change due to new message types in this PR
* swarm/network/stream: generalize SetNextBatch and add Server SessionIndex
* swarm/network/stream: fix a typo in comment
* swarm/network/stream: remove live argument from NewSwarmSyncerServer