connection_maker.go
func (cm *connectionMaker) connectionCreated(conn Connection) {
	cm.actionChan <- func() bool {
		cm.connections[conn] = struct{}{}
		if conn.isOutbound() {
			target := cm.targets[conn.remoteTCPAddress()]
			target.state = targetConnected
		}
		return false
	}
}
func (cm *connectionMaker) connectionCreated(conn Connection) {
	cm.actionChan <- func() bool {
		cm.connections[conn] = struct{}{}
		if conn.isOutbound() {
			target := cm.targets[conn.remoteTCPAddress()]
			target.state = targetConnected
		}
		return false
	}
}
// connectionCreated registers the passed connection, and marks the target
// identified by conn.RemoteTCPAddr() as established, and puts it in the
// TargetConnected state.