Selective export (#770)

vendor/github.com/modern-go/concurrent/executor.go

@@ -2,6 +2,13 @@ package concurrent
 
 import "context"
 
+// Executor replace go keyword to start a new goroutine
+// the goroutine should cancel itself if the context passed in has been cancelled
+// the goroutine started by the executor, is owned by the executor
+// we can cancel all executors owned by the executor just by stop the executor itself
+// however Executor interface does not Stop method, the one starting and owning executor
+// should use the concrete type of executor, instead of this interface.
 type Executor interface {
+	// Go starts a new goroutine controlled by the context
 	Go(handler func(ctx context.Context))
-}
+}