OptionalfilterAn optional filter can prevent duplicate topology notifications for the same peer.
OptionalnotifyIf true, invoke onConnect for this topology on limited connections, e.g.
ones with limits on how much data can be transferred or how long they can
be open for.
OptionalonInvoked when a new connection is opened to a peer that supports the registered protocol
Optionalon
A topology is a network overlay that contains a subset of peers in the complete network.
It is a way to be notified when peers that support a given protocol connect to or disconnect from the current node.