- replace RWMutex with Mutex
- conns now contains `map[int32][]*node`
- add index field to node struct
- add usedAt field to node struct
- `New` don't store current connection twice
- writes `used_at` of connection into the log
- we check that conn is alive and, that connection used not a long time ago, otherwise, close it
- `getConnection` reset current connection and index on errors
- `IsAlive` now is a method of `Pool`
- `IsAlive` creates context with timeout for every health check call of node
- implement connection pool
- wait until container creates
- refactoring gw service
- add config option to enable prometheus and pprof
- update neofs-proto to v0.2.8
