cluster.go
func (c *Cluster) RemoveHost(address *URI) {
	c.mutex.Lock()
	defer c.mutex.Unlock()
	for i, uri := range c.hosts {
		if uri.Equals(address) {
			c.okList[i] = false
			break
		}
	}
}
func (c *Cluster) RemoveHost(address *URI) {
	c.mutex.Lock()
	defer c.mutex.Unlock()
	for i, uri := range c.hosts {
		if uri.Equals(address) {
			c.okList[i] = false
			break
		}
	}
}
// RemoveHost black lists the host with the given URI from the cluster.