Move ServiceUnavailableException to discovery package
Support relative URLs in Request
Create BalancingHttpClient
Create BalancingAsyncHttpClient
Implement binding of balancing http clients
Be stricter about relative URIs
Move discovery announcer into its own package
Extract the code for dealing with service balancing.
Inject the HttpServiceBalancer
Refactor tests to mock the HttpServiceBalancer
Refactor ServiceDescriptorsUpdater out of CachingServiceSelector
Use ServiceDescriptorsUpdater to populate HttpServiceBalancerImpl
Remove support for loading service inventory over http/https.
Create a discovery HttpServiceBalancer from ServiceInventory
Use DiscoveryAsyncHttpClient for talking to discovery service
Pass HttpServiceBalancer exceptions to ResponseHandler
Make ServiceUnavailableException not depend on type/pool.