Logging API for "temporal batches"

[jleibs]

When translating existing time-series plots to Rerun our logging APIs have very poor ergonomics.

A user must iterate through every sample, calling set_time with the time value, and then logging the individual scalars.

The proposal from:

• Stateless time APIs #3841

Would let us optimize this a bit by passing the time values into the log-calls, but will still be order-N which can be quite painful for large time-series.

A direct temporal batch logging API would instead let us collapse this into a single call. For example:

rr.log_temporal_batch(timestamps=[...], ScalarBatch(...))

This would let us dramatically optimize the ingestion by letting us create a pre-batched uniform buffer of scalars that looks like what the eventual output of the batcher is going to be anyways.

[emilk]

• Blocked by The 1M index entries problem #5967

[jleibs]

• New temporal batch APIs #6587 introduces an initial python API.

Missing things to complete this workstream:

• All components should support Batch constructors. #6592
• Egonomic Rust and C++ APIs

[jleibs]

We should do a session on naming and usabillity of this prior to release 0.18