Update files based on go lint

Signed-off-by: Michael Crosby <crosbymichael@gmail.com>

events/events.go

@@ -6,6 +6,7 @@ import (
 	events "github.com/containerd/containerd/api/services/events/v1"
 )
 
+// Event is a generic interface for any type of event
 type Event interface{}
 
 // Publisher posts the event.
@@ -13,6 +14,7 @@ type Publisher interface {
 	Publish(ctx context.Context, topic string, event Event) error
 }
 
+// Forwarder forwards an event to the underlying event bus
 type Forwarder interface {
 	Forward(ctx context.Context, envelope *events.Envelope) error
 }
@@ -23,6 +25,7 @@ func (fn publisherFunc) Publish(ctx context.Context, topic string, event Event)
 	return fn(ctx, topic, event)
 }
 
+// Subscriber allows callers to subscribe to events
 type Subscriber interface {
 	Subscribe(ctx context.Context, filters ...string) (ch <-chan *events.Envelope, errs <-chan error)
 }

events/exchange.go

@@ -18,10 +18,12 @@ import (
 	"github.com/sirupsen/logrus"
 )
 
+// Exchange broadcasts events
 type Exchange struct {
 	broadcaster *goevents.Broadcaster
 }
 
+// NewExchange returns a new event Exchange
 func NewExchange() *Exchange {
 	return &Exchange{
 		broadcaster: goevents.NewBroadcaster(),