Add DeleteRoutes (public API) to delete callbacks for specific topics…

…, related to eclipse#331.

Signed-off-by: Daichi Tomaru <banaoa7543@gmail.com>

client.go

@@ -111,6 +111,8 @@ type Client interface {
 	// a new go routine.
 	// callback must be safe for concurrent use by multiple goroutines.
 	AddRoute(topic string, callback MessageHandler)
+	// DeleteRoutes allow you to delete handlers for messages on specific topics.
+	DeleteRoutes(topics ...string)
 	// OptionsReader returns a ClientOptionsReader which is a copy of the clientoptions
 	// in use by the client.
 	OptionsReader() ClientOptionsReader
@@ -186,6 +188,13 @@ func (c *client) AddRoute(topic string, callback MessageHandler) {
 	}
 }
 
+// DeleteRoutes allow you to delete handlers for messages on specific topics.
+func (c *client) DeleteRoutes(topics ...string) {
+	for _, topic := range topics {
+		c.msgRouter.deleteRoute(topic)
+	}
+}
+
 // IsConnected returns a bool signifying whether
 // the client is connected or not.
 // connected means that the connection is up now OR it will