public interface HostProvider
A set of hosts a ZooKeeper client should connect to.
Classes implementing this interface must guarantee the following:
* Every call to next() returns an InetSocketAddress. So the iterator never
* The size() of a HostProvider may never be zero.
A HostProvider must return resolved InetSocketAddress instances on next(),
but it's up to the HostProvider, when it wants to do the resolving.
Different HostProvider could be imagined:
* A HostProvider that loads the list of Hosts from an URL or from DNS
* A HostProvider that re-resolves the InetSocketAddress after a timeout.
* A HostProvider that prefers nearby hosts.