rpcclient: Stop client on ctx done.

The passed context was ignored until a reconnect. This kills the client
when the passed context is done. This is much more useful for consumers
who need the client to shut down when their context if finished.

rpcclient/infrastructure.go

@@ -1355,7 +1355,8 @@ func New(config *ConnConfig, ntfnHandlers *NotificationHandlers) (*Client, error
 //
 // This method will error if the client is not configured for websockets, if the
 // connection has already been established, or if none of the connection
-// attempts were successful.
+// attempts were successful. The client will be shut down when the passed
+// context is terminated.
 func (c *Client) Connect(ctx context.Context, retry bool) error {
 	c.mtx.Lock()
 	defer c.mtx.Unlock()
@@ -1367,6 +1368,14 @@ func (c *Client) Connect(ctx context.Context, retry bool) error {
 		return ErrClientAlreadyConnected
 	}
 
+	// Shutdown the client on context cancellation.
+	c.wg.Add(1)
+	go func() {
+		<-ctx.Done()
+		c.Shutdown()
+		c.wg.Done()
+	}()
+
 	// Begin connection attempts.  Increase the backoff after each failed
 	// attempt, up to a maximum of one minute.
 	var backoff time.Duration