client: fix context handling.

* fixes r3labs#131.

client.go

@@ -103,18 +103,26 @@ func (c *Client) SubscribeWithContext(ctx context.Context, stream string, handle
 				return err
 			case msg := <-eventChan:
 				handler(msg)
-			case <- ctx.Done():
+			case <-ctx.Done():
 				return ctx.Err()
 			}
 		}
 	}
 
 	// Apply user specified reconnection strategy or default to standard NewExponentialBackOff() reconnection method
 	var err error
+
+	bCtx, cancel := context.WithCancel(ctx)
+	defer cancel()
 	if c.ReconnectStrategy != nil {
-		err = backoff.RetryNotify(operation, c.ReconnectStrategy, c.ReconnectNotify)
+		err = backoff.RetryNotify(
+			operation,
+			backoff.WithContext(c.ReconnectStrategy, bCtx), c.ReconnectNotify)
 	} else {
-		err = backoff.RetryNotify(operation, backoff.NewExponentialBackOff(), c.ReconnectNotify)
+		err = backoff.RetryNotify(
+			operation,
+			backoff.WithContext(backoff.NewExponentialBackOff(), bCtx),
+			c.ReconnectNotify)
 	}
 	return err
 }
@@ -184,10 +192,17 @@ func (c *Client) SubscribeChanWithContext(ctx context.Context, stream string, ch
 		defer c.cleanup(ch)
 		// Apply user specified reconnection strategy or default to standard NewExponentialBackOff() reconnection method
 		var err error
+
+		bCtx, cancel := context.WithCancel(ctx)
+		defer cancel()
 		if c.ReconnectStrategy != nil {
-			err = backoff.RetryNotify(operation, c.ReconnectStrategy, c.ReconnectNotify)
+			err = backoff.RetryNotify(operation,
+				backoff.WithContext(c.ReconnectStrategy, bCtx),
+				c.ReconnectNotify)
 		} else {
-			err = backoff.RetryNotify(operation, backoff.NewExponentialBackOff(), c.ReconnectNotify)
+			err = backoff.RetryNotify(operation,
+				backoff.WithContext(backoff.NewExponentialBackOff(), bCtx),
+				c.ReconnectNotify)
 		}
 
 		// channel closed once connected