This happens randomly when using conc Pool (pool.New()).

panic: send on closed channel

goroutine 17805 [running]:
config-rd/vendor/github.com/sourcegraph/conc/pool.(*Pool).Go(0xc0005c2000, 0xc0a551e558)
E:/go/src/config-rd/vendor/github.com/sourcegraph/conc/pool/pool.go:45 +0x113
main.doGGSN(0xc0e964b688?, 0x1)
E:/go/src/config-rd/parser.go:63 +0xfd8
main.main.func3.1({{0xc031bbafc0, 0x10}, {0xc031bbafd0, 0x4}, {0xc03c3b36e0, 0x1a}, 0x1, 0x0, {0x0, 0x0}, ...})
E:/go/src/config-rd/main.go:375 +0x1c5