Protobuf service {@code waveserver.ProtocolWaveClientRpc}
Provides streaming wave views. A client requests a possibly filtered view of wavelets in a wave. The response stream contains first a snapshot for each wavelet currently in view, and then deltas for those wavelets. The end of the initial set of snapshots is indicated by a "marker" message. New wavelets may come into view after the marker, resulting in another snapshot. The client may indicate that it already has a snapshot for some wavelets by providing one or more known versions and signatures. If one matches the server history the server will not send a snapshot but will instead begin the stream with an empty delta specifying the resynchronization version. TODO(anorth): - make the first response message a channel id only, then no more channel ids