Echo command sends to all clusters a request for another echo (ping). When clusters receives @echo command then they will send ping to another clusters stored in database. You can use this command to update clusters lists (when sending echo, clusters list from database is included in request as a clusters chain).
To send @echo command just type:
@echo
This will send command to all clusters in network.
Echo command (and @broadcast command) are use special object called SkynetPeer. This object allows to create other connection when cluster is already connected with other (different) cluster.
In simply words - this is "connection in connection". You can read about SkynetPeer in next section.
Note: when @echo was sent then no response is generated (response connection is generating by Peer).
To execute code in Event Listener when @echo is received you should use onEcho() event instead of onResponse().
