graceful restart data race

output.txt

==================
WARNING: DATA RACE
Read at 0x00c421963f64 by goroutine 1774:
  internal/race.Read()
      /home/nathan/go/src/internal/race/race.go:37 +0x38
  sync.(*WaitGroup).Add()
      /home/nathan/go/src/sync/waitgroup.go:71 +0x26b
  github.com/mholt/caddy/caddyhttp/httpserver.(*gracefulListener).Accept()
      /home/nathan/projects/src/github.com/mholt/caddy/caddyhttp/httpserver/graceful.go:45 +0x169
  net/http.(*Server).Serve()
      /home/nathan/go/src/net/http/server.go:2643 +0x2a7
  github.com/mholt/caddy/caddyhttp/httpserver.(*Server).Serve()
      /home/nathan/projects/src/github.com/mholt/caddy/caddyhttp/httpserver/server.go:190 +0x170
  github.com/mholt/caddy.startServers.func1.1()
      /home/nathan/projects/src/github.com/mholt/caddy/caddy.go:667 +0x56

Previous write at 0x00c421963f64 by goroutine 504:
  internal/race.Write()
      /home/nathan/go/src/internal/race/race.go:41 +0x38
  sync.(*WaitGroup).Wait()
      /home/nathan/go/src/sync/waitgroup.go:129 +0x14b
  github.com/mholt/caddy/caddyhttp/httpserver.(*Server).Stop.func1()
      /home/nathan/projects/src/github.com/mholt/caddy/caddyhttp/httpserver/server.go:323 +0x58

Goroutine 1774 (running) created at:
  github.com/mholt/caddy.startServers.func1()
      /home/nathan/projects/src/github.com/mholt/caddy/caddy.go:669 +0xce

Goroutine 504 (running) created at:
  github.com/mholt/caddy/caddyhttp/httpserver.(*Server).Stop()
      /home/nathan/projects/src/github.com/mholt/caddy/caddyhttp/httpserver/server.go:325 +0xb9
  github.com/mholt/caddy.(*Instance).Stop()
      /home/nathan/projects/src/github.com/mholt/caddy/caddy.go:98 +0x43e
  github.com/mholt/caddy.(*Instance).Restart()
      /home/nathan/projects/src/github.com/mholt/caddy/caddy.go:197 +0x6c3
  github.com/mholt/caddy.trapSignalsPosix.func1()
      /home/nathan/projects/src/github.com/mholt/caddy/sigtrap_posix.go:77 +0x567
==================


panic: sync: WaitGroup is reused before previous Wait has returned

goroutine 70798 [running]:
sync.(*WaitGroup).Wait(0xc421963f58)
	/home/nathan/go/src/sync/waitgroup.go:133 +0x138
github.com/mholt/caddy/caddyhttp/httpserver.(*Server).Stop.func1(0xc421963f10, 0xc42236fec0)
	/home/nathan/projects/src/github.com/mholt/caddy/caddyhttp/httpserver/server.go:323 +0x59
created by github.com/mholt/caddy/caddyhttp/httpserver.(*Server).Stop
	/home/nathan/projects/src/github.com/mholt/caddy/caddyhttp/httpserver/server.go:325 +0xba