New creates a new Retriever.

ErrConsumerAlreadyRegistered is returned if a consumer is already registered.

ErrInitialCallTimeout is returned if the initial clusterinfo call timed out.

Response is the cluster info retrievable from the / endpoint.

Retriever periodically gets the cluster info from the / endpoint and sends it to all registered consumer channels.

VersionInfo is the version info retrievable from the / endpoint, embedded in Response.