Close chanel when job is done

Author: vardius

README.md

@@ -34,11 +34,11 @@ HOW TO USE
 goos: darwin
 goarch: amd64
 pkg: github.com/vardius/gollback
-BenchmarkRace-4    	 5000000	       223 ns/op	       0 B/op	       0 allocs/op
-BenchmarkAll-4     	 5000000	       281 ns/op	      40 B/op	       1 allocs/op
+BenchmarkRace-4    	  500000	      2961 ns/op	     668 B/op	       5 allocs/op
+BenchmarkAll-4     	 5000000	       273 ns/op	      40 B/op	       1 allocs/op
 BenchmarkRetry-4   	200000000	         6.68 ns/op	       0 B/op	       0 allocs/op
 PASS
-ok  	github.com/vardius/gollback	25.130s
+ok  	github.com/vardius/gollback	32.418s
 ```
 
 ## Race

gollback.go

@@ -31,14 +31,16 @@ type response struct {
 }
 
 func (p *gollback) Race(fns ...AsyncFunc) (interface{}, error) {
-	ctx, cancel := context.WithCancel(p.ctx)
 	out := make(chan *response, 1)
+	ctx, cancel := context.WithCancel(p.ctx)
+	defer cancel()
 
 	for i, fn := range fns {
 		go func(index int, f AsyncFunc) {
 			c := make(chan *response, 1)
 
 			go func() {
+				defer close(c)
 				var r response
 				r.res, r.err = f(ctx)
 
@@ -67,7 +69,6 @@ func (p *gollback) Race(fns ...AsyncFunc) (interface{}, error) {
 	}
 
 	r := <-out
-	cancel()
 
 	return r.res, r.err
 }