add event dispose

lib/client.js

@@ -44,6 +44,10 @@ class Client{
                 this.callback_message_queue[key](new Error('close connect'))
                 delete this.callback_message_queue[key]
             })
+            ['server.peers.subscribe',
+             'blockchain.numblocks.subscribe',
+             'blockchain.headers.subscribe',
+             'blockchain.address.subscribe'].forEach(event => this.subscribe.removeAllListeners(event))
         })
         conn.on('data', (chunk) => {
             this.mp.run(chunk)