Multiple race conditions

[tomkukral]

There are multiple race conditions

WARNING: DATA RACE
Write at 0x00c00011e3e0 by goroutine 7:
  github.com/zenthangplus/goccm.(*concurrencyManager).Close()
      /home/tom/src/tomkukral/goccm/goccm.go:109 +0x18d
  github.com/zenthangplus/goccm.(*concurrencyManager).WaitAllDone()
      /home/tom/src/tomkukral/goccm/goccm.go:115 +0x181
  github.com/zenthangplus/goccm.TestExample()
      /home/tom/src/tomkukral/goccm/goccm_test.go:19 +0x180
  testing.tRunner()
      /opt/golang/1.19.3/src/testing/testing.go:1446 +0x216
  testing.(*T).Run.func1()
      /opt/golang/1.19.3/src/testing/testing.go:1493 +0x47

Previous read at 0x00c00011e3e0 by goroutine 8:
  github.com/zenthangplus/goccm.(*concurrencyManager).controller()
      /home/tom/src/tomkukral/goccm/goccm.go:78 +0x88
  github.com/zenthangplus/goccm.New.func1()
      /home/tom/src/tomkukral/goccm/goccm.go:61 +0x39

Goroutine 7 (running) created at:
  testing.(*T).Run()
      /opt/golang/1.19.3/src/testing/testing.go:1493 +0x75d
  testing.runTests.func1()
      /opt/golang/1.19.3/src/testing/testing.go:1846 +0x99
  testing.tRunner()
      /opt/golang/1.19.3/src/testing/testing.go:1446 +0x216
  testing.runTests()
      /opt/golang/1.19.3/src/testing/testing.go:1844 +0x7ec
  testing.(*M).Run()
      /opt/golang/1.19.3/src/testing/testing.go:1726 +0xa84
  main.main()
      _testmain.go:51 +0x2e9

Goroutine 8 (running) created at:
  github.com/zenthangplus/goccm.New()
      /home/tom/src/tomkukral/goccm/goccm.go:61 +0x1d6
  github.com/zenthangplus/goccm.TestExample()
      /home/tom/src/tomkukral/goccm/goccm_test.go:10 +0x2e
  testing.tRunner()
      /opt/golang/1.19.3/src/testing/testing.go:1446 +0x216
  testing.(*T).Run.func1()
      /opt/golang/1.19.3/src/testing/testing.go:1493 +0x47