Found data race in the "tcpServer"

[mstmdev]

Running command (Windows 10)

$ go version
go version go1.17.6 windows/amd64

$ cd E:/workspace/gowork/src/github.com/no-src/gofs
$ mkdir rs\source rs\dest rc\source rc\dest
# server
$ go run -race ./cmd/gofs -source="rs://127.0.0.1:9016?mode=server&local_sync_disabled=true&path=./rs/source" -dest=./rs/dest -tls_cert_file=./gofs.pem -tls_key_file=./gofs.key -users="u1234|p4321"
# client
$ go run -race ./cmd/gofs -source="rs://127.0.0.1:9016" -dest=./rc/dest -users="u1234|p4321"

Server error info

==================
WARNING: DATA RACE
Write at 0x00c00002c690 by goroutine 15:
  runtime.mapassign_faststr()
      C:/Go/src/runtime/map_faststr.go:202 +0x0
  github.com/no-src/gofs/tran.(*tcpServer).addClient()
      E:/workspace/gowork/src/github.com/no-src/gofs/tran/tcpserver.go:120 +0x107
  github.com/no-src/gofs/tran.(*tcpServer).Accept()
      E:/workspace/gowork/src/github.com/no-src/gofs/tran/tcpserver.go:91 +0xea
  github.com/no-src/gofs/sync.(*remoteServerSync).start·dwrap·3()
      E:/workspace/gowork/src/github.com/no-src/gofs/sync/remote_server_sync.go:209 +0x59

Previous read at 0x00c00002c690 by goroutine 20:
  runtime.mapiterinit()
      C:/Go/src/runtime/map.go:802 +0x0
  github.com/no-src/gofs/tran.(*tcpServer).Send()
      E:/workspace/gowork/src/github.com/no-src/gofs/tran/tcpserver.go:147 +0xa7
  github.com/no-src/gofs/sync.(*remoteServerSync).send()
      E:/workspace/gowork/src/github.com/no-src/gofs/sync/remote_server_sync.go:189 +0x7b2
  github.com/no-src/gofs/sync.(*remoteServerSync).Write()
      E:/workspace/gowork/src/github.com/no-src/gofs/sync/remote_server_sync.go:90 +0x7d
  github.com/no-src/gofs/monitor.(*baseMonitor).startSyncWrite.func1()
      E:/workspace/gowork/src/github.com/no-src/gofs/monitor/base_monitor.go:121 +0x67
  github.com/no-src/gofs/retry.(*defaultRetry).DoWithContext()
      E:/workspace/gowork/src/github.com/no-src/gofs/retry/default_retry.go:40 +0x161
  github.com/no-src/gofs/retry.(*defaultRetry).Do()
      E:/workspace/gowork/src/github.com/no-src/gofs/retry/default_retry.go:29 +0x6b
  github.com/no-src/gofs/monitor.(*baseMonitor).startSyncWrite()
      E:/workspace/gowork/src/github.com/no-src/gofs/monitor/base_monitor.go:120 +0x241
  github.com/no-src/gofs/monitor.(*fsNotifyMonitor).Start·dwrap·2()
      E:/workspace/gowork/src/github.com/no-src/gofs/monitor/fsnotify_monitor.go:97 +0x39

Goroutine 15 (running) created at:
  github.com/no-src/gofs/sync.(*remoteServerSync).start()
      E:/workspace/gowork/src/github.com/no-src/gofs/sync/remote_server_sync.go:209 +0x23b
  github.com/no-src/gofs/sync.NewRemoteServerSync()
      E:/workspace/gowork/src/github.com/no-src/gofs/sync/remote_server_sync.go:72 +0x6ce
  github.com/no-src/gofs/sync.NewRemoteSync()
      E:/workspace/gowork/src/github.com/no-src/gofs/sync/remote_sync.go:11 +0x164
  github.com/no-src/gofs/sync.NewSync()
      E:/workspace/gowork/src/github.com/no-src/gofs/sync/sync.go:36 +0x464
  main.main()
      E:/workspace/gowork/src/github.com/no-src/gofs/cmd/gofs/main.go:118 +0x10b9

Goroutine 20 (running) created at:
  github.com/no-src/gofs/monitor.(*fsNotifyMonitor).Start()
      E:/workspace/gowork/src/github.com/no-src/gofs/monitor/fsnotify_monitor.go:97 +0x377
  main.main()
      E:/workspace/gowork/src/github.com/no-src/gofs/cmd/gofs/main.go:157 +0x1631
==================

[mstmdev]

fixed by #11